diff --git a/CLAUDE.md b/CLAUDE.md
index a86f18f..29963b4 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -1,1392 +1,90 @@
-# CLAUDE.md - Project Context & Instructions
+# CLAUDE.md - Class Generator 2.0
 
-## 📋 Project Overview
+## 📋 Overview
+Educational platform with ultra-modular vanilla JS/HTML/CSS architecture. Strict separation, sealed modules, dependency injection.
 
-**Class Generator 2.0** - Complete rewrite of educational games platform with ultra-modular architecture.
+## 🏗️ Status
 
-### 🎯 Current Mission
-Building a **bulletproof modular system** with strict separation of concerns using vanilla JavaScript, HTML, and CSS. The architecture enforces inviolable responsibility patterns with sealed modules and dependency injection.
+**Core ✅**: Module.js, EventBus.js, ModuleLoader.js, Router.js, Application.js, Dev Server
+**DRS ✅**: ContentLoader, IAEngine (OpenAI→DeepSeek), LLMValidator, AI Reports, UnifiedDRS
+**Exercises ✅**: VocabularyModule, TextAnalysis, GrammarAnalysis, Translation, OpenResponse
+**AI ✅**: Production ready, strict scoring (wrong: 0-20, correct: 70-100), no mock fallbacks
 
-### 🏗️ Architecture Status
+## ⚠️ Critical Rules
 
-**PHASE 1 COMPLETED ✅** - Core foundation built with rigorous architectural patterns:
-- ✅ **Module.js** - Abstract base class with WeakMap privates and sealed instances
-- ✅ **EventBus.js** - Strict event system with validation and module registration
-- ✅ **ModuleLoader.js** - Dependency injection with proper initialization order
-- ✅ **Router.js** - Navigation with guards, middleware, and state management
-- ✅ **Application.js** - Auto-bootstrap system with lifecycle management
-- ✅ **Development Server** - HTTP server with ES6 modules and CORS support
+### Architecture (NON-NEGOTIABLE)
+1. **Single responsibility** per module
+2. **EventBus only** for communication (no direct deps)
+3. **Object.seal()** prevents modification
+4. **WeakMap** for private state
+5. **Abstract enforcement** - missing methods = fatal error
+6. **Dependency injection** - no globals
 
-**DRS SYSTEM COMPLETED ✅** - Advanced learning modules with dual AI approach:
-
-**Core Exercise Generation:**
-- ✅ **ContentLoader** - Pure AI content generation when no real content available
-- ✅ **IAEngine** - Multi-provider AI system (OpenAI → DeepSeek → Hard Fail)
-- ✅ **LLMValidator** - Intelligent answer validation with detailed feedback
-- ✅ **AI Report System** - Session tracking with exportable reports (text/HTML/JSON)
-- ✅ **UnifiedDRS** - Component-based exercise presentation system
-
-**DRS Exercise Modules:**
-- ✅ **Vocabulary Flashcards** - VocabularyModule provides spaced repetition learning (local validation, no AI)
-- ✅ **Intelligent QCM** - AI generates questions + 1 correct + 5 plausible wrong answers (16.7% random chance)
-- ✅ **Open Analysis Modules** - Free-text responses validated by AI with personalized feedback
-  - ✅ TextAnalysisModule - Deep comprehension with AI coaching (0-100 strict scoring)
-  - ✅ GrammarAnalysisModule - Grammar correction with explanations (0-100 strict scoring)
-  - ✅ TranslationModule - Translation validation with multi-language support (0-100 strict scoring)
-  - ✅ OpenResponseModule - Free-form questions with intelligent evaluation
-
-**AI Architecture - PRODUCTION READY:**
-- ✅ **AI-Mandatory System** - No mock/fallback, real AI only, ensures educational quality
-- ✅ **Strict Scoring Logic** - Wrong answers: 0-20 points, Correct answers: 70-100 points
-- ✅ **Multi-Provider Fallback** - OpenAI → DeepSeek → Hard Fail (no fake responses)
-- ✅ **Comprehensive Testing** - 100% validation with multiple test scenarios
-- ✅ **Smart Prompt Engineering** - Context-aware prompts with proper language detection
-- ⚠️ **Cache System** - Currently disabled for testing (see Cache Management section)
-
-## ⚠️ CRITICAL ARCHITECTURAL SEPARATION
-
-### 🎯 DRS vs Games - NEVER MIX
-
-**DRS (Dynamic Response System)** - Educational exercise modules in `src/DRS/`:
-- ✅ **VocabularyModule.js** - Spaced repetition flashcards (local validation)
-- ✅ **TextAnalysisModule.js** - AI-powered text comprehension
-- ✅ **GrammarAnalysisModule.js** - AI grammar correction
-- ✅ **TranslationModule.js** - AI translation validation
-- ✅ **All modules in `src/DRS/`** - Educational exercises with strict interface compliance
-
-**Games** - Independent game modules in `src/games/`:
-- ❌ **FlashcardLearning.js** - Standalone flashcard game (NOT part of DRS)
-- ❌ **Other game modules** - Entertainment-focused, different architecture
-- ❌ **NEVER import games into DRS** - Violates separation of concerns
-
-### 🚫 FORBIDDEN MIXING
-```javascript
-// ❌ NEVER DO THIS - DRS importing games
-import FlashcardLearning from '../games/FlashcardLearning.js';
-
-// ✅ CORRECT - DRS uses its own modules
-import VocabularyModule from './exercise-modules/VocabularyModule.js';
-```
-
-**Rule**: **DRS = Educational Exercises**, **Games = Entertainment**. They MUST remain separate.
-
-## 🔥 Critical Requirements
-
-### Architecture Principles (NON-NEGOTIABLE)
-1. **Inviolable Responsibility** - Each module has exactly one purpose
-2. **Zero Direct Dependencies** - All communication via EventBus only
-3. **Sealed Instances** - Modules cannot be modified after creation
-4. **Private State** - Internal data completely inaccessible via WeakMap
-5. **Contract Enforcement** - Abstract methods must be implemented
-6. **Dependency Injection** - No globals, everything injected through constructor
+### DRS vs Games - NEVER MIX
+- **DRS** (`src/DRS/`) = Educational exercises with strict interfaces
+- **Games** (`src/games/`) = Entertainment, different architecture
+- ❌ NEVER `import FlashcardLearning from '../games/'` in DRS
+- ✅ ALWAYS `import VocabularyModule from './exercise-modules/'` in DRS
 
 ### Technical Constraints
-- **Vanilla JS/HTML/CSS only** - No frameworks
-- **ES6 Modules** - Import/export syntax required
-- **HTTP Protocol** - Never file:// (use development server)
-- **Modular CSS** - Component-scoped styling
-- **Event-Driven** - No direct module coupling
+- Vanilla JS/HTML/CSS only (no frameworks)
+- ES6 modules, HTTP protocol (never file://)
+- **NO SCROLL** - all UI fits viewport height
+- Mobile-first, compact headers, vertical space precious
 
-### UI/UX Design Principles (CRITICAL)
-- **NO SCROLL POLICY** - All interfaces MUST fit within viewport height without scrolling
-- **Height Management** - Vertical space is precious, horizontal space is abundant
-- **Compact Navigation** - Top bars and headers must be minimal height
-- **Responsive Layout** - Use available width, preserve viewport height
-- **Mobile-First** - Design for smallest screens first, then scale up
+### Development DO's/DON'Ts
+✅ Extend Module base, use EventBus, validate deps, seal objects, simple solutions first
+❌ Never access internals, globals, skip validation, hardcode paths, overcomplicate positioning
 
-## 🚀 Development Workflow
-
-### Starting the System
+## 🚀 Quick Start
 ```bash
-# Option 1: Windows batch file
-start.bat
-
-# Option 2: Node.js directly
-node server.js
-
-# Option 3: NPM scripts
-npm start
+start.bat  # or: node server.js
+# http://localhost:3000
 ```
 
-**Access:** http://localhost:3000
-
-### Development Server Features
-- ✅ ES6 modules support
-- ✅ CORS enabled for online communication
-- ✅ Proper MIME types for all file formats
-- ✅ Development-friendly caching (assets cached, HTML not cached)
-- ✅ Graceful error handling with styled 404 pages
-
-## 📁 Project Structure
-
+## 📁 Structure
 ```
-├── src/
-│   ├── core/              # COMPLETED - Core system (sealed)
-│   │   ├── Module.js      # Abstract base class
-│   │   ├── EventBus.js    # Event communication system
-│   │   ├── ModuleLoader.js # Dependency injection
-│   │   ├── Router.js      # Navigation system
-│   │   └── index.js       # Core exports
-│   ├── DRS/              # COMPLETED - DRS educational modules
-│   │   ├── exercise-modules/ # Educational exercise modules
-│   │   ├── services/      # AI and validation services
-│   │   └── interfaces/    # Module interfaces
-│   ├── games/            # SEPARATE - Independent game modules
-│   │   └── FlashcardLearning.js # External flashcard game (NOT part of DRS)
-│   ├── components/        # TODO - UI components
-│   ├── content/          # TODO - Content system
-│   ├── styles/           # COMPLETED - Modular CSS
-│   │   ├── base.css      # Foundation styles
-│   │   └── components.css # Reusable UI components
-│   └── Application.js    # COMPLETED - Bootstrap system
-├── Legacy/               # Archived old system
-├── index.html           # COMPLETED - Entry point
-├── server.js            # COMPLETED - Development server
-├── start.bat            # COMPLETED - Quick start script
-├── package.json         # COMPLETED - Node.js config
-└── README.md            # COMPLETED - Documentation
+src/
+├── core/          # Module, EventBus, ModuleLoader, Router, Application
+├── DRS/           # Exercise modules, services, interfaces
+├── games/         # Independent game modules (NOT DRS)
+├── styles/        # base.css, components.css
+└── Application.js # Bootstrap
 ```
 
-## 🎮 Creating New Modules
+## 📚 Documentation
 
-### Game Module Template
+**Core Guides:**
+- `docs/architecture.md` - Architecture principles and patterns
+- `docs/creating-new-module.md` - How to create new modules (Game, DRS, Progress)
+- `docs/interfaces.md` - Interface system (C++ style contracts)
+- `docs/progress-system.md` - Progress tracking and prerequisites
+
+## 🔍 Debug
 ```javascript
-import Module from '../core/Module.js';
-
-class GameName extends Module {
-    constructor(name, dependencies, config) {
-        super(name, ['eventBus']); // Declare dependencies
-
-        // Validate dependencies
-        if (!dependencies.eventBus) {
-            throw new Error('GameName requires EventBus dependency');
-        }
-
-        this._eventBus = dependencies.eventBus;
-        this._config = config;
-
-        Object.seal(this); // Prevent modification
-    }
-
-    async init() {
-        this._validateNotDestroyed();
-
-        // Set up event listeners
-        this._eventBus.on('game:start', this._handleStart.bind(this), this.name);
-
-        this._setInitialized();
-    }
-
-    async destroy() {
-        this._validateNotDestroyed();
-
-        // Cleanup logic here
-
-        this._setDestroyed();
-    }
-
-    // Private methods
-    _handleStart(event) {
-        this._validateInitialized();
-        // Game logic here
-    }
-}
-
-export default GameName;
-```
-
-### Registration in Application.js
-```javascript
-modules: [
-    {
-        name: 'gameName',
-        path: './games/GameName.js',
-        dependencies: ['eventBus'],
-        config: { difficulty: 'medium' }
-    }
-]
-```
-
-## 🔍 Debugging & Monitoring
-
-### Debug Panel (F12 to toggle)
-- System status and uptime
-- Loaded modules list
-- Event history
-- Module registration status
-
-### Console Access
-```javascript
-window.app.getStatus()                    // Application status
-window.app.getCore().eventBus            // EventBus instance
-window.app.getCore().moduleLoader        // ModuleLoader instance
-window.app.getCore().router              // Router instance
-```
-
-### Common Commands
-```bash
-# Check module status
-window.app.getCore().moduleLoader.getStatus()
-
-# View event history
+// F12 toggles debug panel
+window.app.getStatus()
 window.app.getCore().eventBus.getEventHistory()
-
-# Navigate programmatically
 window.app.getCore().router.navigate('/games')
 ```
 
-## 🚧 Next Development Phase
-
-### Immediate Tasks (PHASE 2)
-1. ❌ **Component-based UI System** - Reusable UI components with scoped CSS
-2. ❌ **Example Game Module** - Simple memory game to validate architecture
-3. ❌ **Content System Integration** - Port content loading from Legacy
-4. ❌ **Testing Framework** - Validate module contracts and event flow
-
-### 📚 DRS Flashcard System
-
-**VocabularyModule.js** serves as the DRS's integrated flashcard system:
-- ✅ **Spaced Repetition** - Again, Hard, Good, Easy difficulty selection
-- ✅ **Local Validation** - No AI required, simple string matching with fuzzy logic
-- ✅ **Mastery Tracking** - Integration with PrerequisiteEngine
-- ✅ **Word Discovery Integration** - WordDiscoveryModule transitions to VocabularyModule
-- ✅ **Full UI** - Card-based interface with pronunciation, progress tracking
-
-**This eliminates the need for external flashcard games in DRS context.**
-
-### Known Legacy Issues to Fix
-31 bug fixes and improvements from the old system:
-- Grammar game functionality issues
-- Word Storm duration and difficulty problems
-- Memory card display issues
-- Adventure game text repetition
-- UI alignment and feedback issues
-- Performance optimizations needed
-
-## 🔒 Security & Rigidity Enforcement
-
-### Module Protection Layers
-1. **Object.seal()** - Prevents property addition/deletion
-2. **Object.freeze()** - Prevents prototype modification
-3. **WeakMap privates** - Internal state completely hidden
-4. **Abstract enforcement** - Missing methods throw errors
-5. **Validation at boundaries** - All inputs validated
-
-### Error Messages
-The system provides explicit error messages for violations:
-- "Module is abstract and cannot be instantiated directly"
-- "Module name is required and must be a string"
-- "EventBus requires module registration before use"
-- "Module must be initialized before use"
-
-## 📝 Development Guidelines
-
-### DO's
-- ✅ Always extend Module base class for game modules
-- ✅ Use EventBus for all inter-module communication
-- ✅ Validate dependencies in constructor
-- ✅ Call `_setInitialized()` after successful init
-- ✅ Use private methods with underscore prefix
-- ✅ Seal objects to prevent modification
-- ✅ **Start with simple solutions first** - Test basic functionality before adding complexity
-- ✅ **Test code in console first** - Validate logic with quick console tests before file changes
-
-### DON'Ts
-- ❌ Never access another module's internals directly
-- ❌ Never use global variables for communication
-- ❌ Never modify Module base class or core system
-- ❌ Never skip dependency validation
-- ❌ Never use file:// protocol (always use HTTP server)
-- ❌ **NEVER HARDCODE JSON PATHS** - Always use dynamic paths based on selected book/chapter
-- ❌ **Never overcomplicate positioning logic** - Use simple CSS transforms (translate(-50%, -50%)) for centering before complex calculations
-
-## 🧠 Problem-Solving Best Practices
-
-### UI Positioning Issues
-1. **Start Simple**: Use basic CSS positioning (center with transform) first
-2. **Test in Console**: Validate positioning logic with `console.log` and direct DOM manipulation
-3. **Check Scope**: Ensure variables like `contentLoader` are globally accessible when needed
-4. **Cache-bust**: Add `?v=2` to CSS/JS files when browser cache causes issues
-5. **Verify Real Dimensions**: Use `getBoundingClientRect()` only when basic centering fails
-
-### Debugging Workflow
-1. **Console First**: Test functions directly in browser console before modifying files
-2. **Log Everything**: Add extensive logging to understand execution flow
-3. **One Change at a Time**: Make incremental changes and test each step
-4. **Simple Solutions Win**: Prefer `left: 50%; transform: translateX(-50%)` over complex calculations
+## 🗄️ AI Cache
+Cache currently disabled for testing. See `IAEngine.js` lines 165-170.
+**Why**: 100-char cache key too short. **Fix**: Improve to 200+ chars with language/exerciseType/contentHash.
 
 ## 🎯 Success Metrics
+- **<100ms** module loading
+- **<50ms** event propagation
+- **<200ms** startup
+- **Zero** memory leaks
+- **Zero** direct coupling
 
-### Architecture Quality
-- **Zero direct coupling** between modules
-- **100% sealed instances** - no external modification possible
-- **Complete test coverage** of module contracts
-- **Event-driven communication** only
-
-### Performance Targets
-- **<100ms** module loading time
-- **<50ms** event propagation time
-- **<200ms** application startup time
-- **Zero memory leaks** in module lifecycle
-
-## 🔄 Migration Notes
-
-### From Legacy System
-The `Legacy/` folder contains the complete old system. Key architectural changes:
-
-**Old Approach:**
-- Global variables and direct coupling
-- Manual module registration
-- CSS modifications in global files
-- Mixed responsibilities in single files
-
-**New Approach:**
-- Strict modules with dependency injection
-- Automatic loading with dependency resolution
-- Component-scoped CSS injection
-- Single responsibility per module
-
-### Data Migration
-- Content modules need adaptation to new Module base class
-- Game logic needs EventBus integration
-- CSS needs component scoping
-- Configuration needs dependency declaration
+## 🚧 Next Phase
+1. Component-based UI system
+2. Example game module
+3. Content system integration
+4. Testing framework
 
 ---
 
-## 📋 COMPREHENSIVE TEST CHECKLIST
-
-### 🏗️ Architecture Tests
-
-#### Core System Tests
-- [ ] **Module.js Tests**
-  - [ ] Abstract class cannot be instantiated directly
-  - [ ] WeakMap private data is truly private
-  - [ ] Object.seal() prevents modification
-  - [ ] Lifecycle methods work correctly (init, destroy)
-  - [ ] Validation methods throw appropriate errors
-
-- [ ] **EventBus.js Tests**
-  - [ ] Event registration and deregistration
-  - [ ] Module validation before event usage
-  - [ ] Event history tracking
-  - [ ] Cross-module communication isolation
-  - [ ] Memory leak prevention on module destroy
-
-- [ ] **ModuleLoader.js Tests**
-  - [ ] Dependency injection order
-  - [ ] Circular dependency detection
-  - [ ] Module initialization sequence
-  - [ ] Error handling for missing dependencies
-  - [ ] Module unloading and cleanup
-
-- [ ] **Router.js Tests**
-  - [ ] Navigation guards functionality
-  - [ ] Middleware execution order
-  - [ ] State management
-  - [ ] URL parameter handling
-  - [ ] History management
-
-- [ ] **Application.js Tests**
-  - [ ] Auto-bootstrap system
-  - [ ] Lifecycle management
-  - [ ] Module registration
-  - [ ] Error recovery
-  - [ ] Debug panel functionality
-
-### 🎮 DRS System Tests
-
-#### Module Interface Tests
-- [ ] **ExerciseModuleInterface Tests**
-  - [ ] All required methods implemented
-  - [ ] Method signatures correct
-  - [ ] Error throwing for abstract methods
-
-#### Individual Module Tests
-- [ ] **TextModule Tests**
-  - [ ] Text loading and display
-  - [ ] Question generation/extraction
-  - [ ] AI validation with fallback
-  - [ ] Progress tracking
-  - [ ] UI interaction (buttons, inputs)
-  - [ ] Viewing time tracking
-  - [ ] Results calculation
-
-- [ ] **AudioModule Tests**
-  - [ ] Audio playback controls
-  - [ ] Playback counting
-  - [ ] Transcript reveal timing
-  - [ ] AI audio analysis
-  - [ ] Progress tracking
-  - [ ] Penalty system for excessive playbacks
-
-- [ ] **ImageModule Tests**
-  - [ ] Image loading and display
-  - [ ] Zoom functionality
-  - [ ] Observation time tracking
-  - [ ] AI vision analysis
-  - [ ] Question types (description, details, interpretation)
-  - [ ] Progress tracking
-
-- [ ] **GrammarModule Tests**
-  - [ ] Rule explanation display
-  - [ ] Exercise type variety (fill-blank, correction, etc.)
-  - [ ] Hint system
-  - [ ] Attempt tracking
-  - [ ] AI grammar analysis
-  - [ ] Scoring with penalties/bonuses
-
-### 🤖 AI Integration Tests
-
-#### AI Provider Tests
-- [ ] **OpenAI Integration**
-  - [ ] API connectivity test
-  - [ ] Response format validation
-  - [ ] Error handling
-  - [ ] Timeout management
-
-- [ ] **DeepSeek Integration**
-  - [ ] API connectivity test
-  - [ ] Fallback from OpenAI
-  - [ ] Response format validation
-  - [ ] Error handling
-
-- [ ] **AI Fallback System**
-  - [ ] Provider switching logic
-  - [ ] Graceful degradation to basic validation
-  - [ ] Status tracking and reporting
-  - [ ] Recovery mechanisms
-
-#### Response Parsing Tests
-- [ ] **Structured Response Parsing**
-  - [ ] [answer]yes/no extraction
-  - [ ] [explanation] extraction
-  - [ ] Error handling for malformed responses
-  - [ ] Multiple format support
-
-### 💾 Data Persistence Tests
-
-#### Progress Tracking Tests
-- [ ] **Mastery Tracking**
-  - [ ] Timestamp recording
-  - [ ] Metadata storage
-  - [ ] Progress calculation
-  - [ ] Persistent storage integration
-
-- [ ] **Data Merge System**
-  - [ ] Local vs external data merging
-  - [ ] Conflict resolution strategies
-  - [ ] Import/export functionality
-  - [ ] Data integrity validation
-
-### 🎨 UI/UX Tests
-
-#### Design Principles Tests
-- [ ] **No Scroll Policy**
-  - [ ] All interfaces fit viewport height
-  - [ ] Responsive breakpoint testing
-  - [ ] Mobile viewport compliance
-
-- [ ] **Responsive Design**
-  - [ ] Mobile-first approach validation
-  - [ ] Horizontal space utilization
-  - [ ] Vertical space conservation
-
-#### Component Tests
-- [ ] **Button Interactions**
-  - [ ] Hover effects
-  - [ ] Disabled states
-  - [ ] Click handlers
-  - [ ] Loading states
-
-- [ ] **Form Controls**
-  - [ ] Input validation
-  - [ ] Error display
-  - [ ] Accessibility compliance
-  - [ ] Keyboard navigation
-
-### 🌐 Network & Server Tests
-
-#### Development Server Tests
-- [ ] **ES6 Modules Support**
-  - [ ] Import/export functionality
-  - [ ] MIME type handling
-  - [ ] CORS configuration
-
-- [ ] **Caching Strategy**
-  - [ ] Assets cached correctly
-  - [ ] HTML not cached for development
-  - [ ] Cache invalidation
-
-- [ ] **Error Handling**
-  - [ ] 404 page display
-  - [ ] Graceful error recovery
-  - [ ] Error message clarity
-
-### 🔄 Integration Tests
-
-#### End-to-End Scenarios
-- [ ] **Complete Exercise Flow**
-  - [ ] Module loading
-  - [ ] Exercise presentation
-  - [ ] User interaction
-  - [ ] AI validation
-  - [ ] Progress saving
-  - [ ] Results display
-
-- [ ] **Multi-Module Navigation**
-  - [ ] Module switching
-  - [ ] State preservation
-  - [ ] Memory cleanup
-
-- [ ] **Data Persistence Flow**
-  - [ ] Progress tracking across sessions
-  - [ ] Data export/import
-  - [ ] Sync functionality
-
-### ⚡ Performance Tests
-
-#### Loading Performance
-- [ ] **Module Loading Times**
-  - [ ] <100ms module loading
-  - [ ] <50ms event propagation
-  - [ ] <200ms application startup
-
-#### Memory Management
-- [ ] **Memory Leaks**
-  - [ ] Module cleanup verification
-  - [ ] Event listener removal
-  - [ ] DOM element cleanup
-
-### 🔒 Security Tests
-
-#### Module Isolation Tests
-- [ ] **Private State Protection**
-  - [ ] WeakMap data inaccessible
-  - [ ] Sealed object modification prevention
-  - [ ] Cross-module boundary enforcement
-
-#### Input Validation Tests
-- [ ] **Boundary Validation**
-  - [ ] All inputs validated
-  - [ ] Error messages for violations
-  - [ ] Malicious input handling
-
-### 🎯 TESTING PRIORITY
-
-#### **HIGH PRIORITY** (Core System)
-1. Module.js lifecycle and sealing tests
-2. EventBus communication isolation
-3. ModuleLoader dependency injection
-4. Basic DRS module functionality
-
-#### **MEDIUM PRIORITY** (Integration)
-1. AI provider fallback system
-2. Data persistence and merging
-3. UI/UX compliance tests
-4. End-to-end exercise flows
-
-#### **LOW PRIORITY** (Polish)
-1. Performance benchmarks
-2. Advanced security tests
-3. Edge case scenarios
-4. Browser compatibility
-
----
-
-## 🗄️ AI Cache Management
-
-### Current Status
-The AI response cache system is **currently disabled** to ensure accurate testing and debugging of the scoring logic.
-
-### Cache System Overview
-The cache improves performance and reduces API costs by storing AI responses for similar prompts.
-
-**Cache Logic (src/DRS/services/IAEngine.js):**
-```javascript
-// Lines 165-170: Cache check (currently commented out)
-const cacheKey = this._generateCacheKey(prompt, options);
-if (this.cache.has(cacheKey)) {
-    this.stats.cacheHits++;
-    this._log('📦 Cache hit for educational validation');
-    return this.cache.get(cacheKey);
-}
-
-// Lines 198: Cache storage (still active)
-this.cache.set(cacheKey, result);
-```
-
-### ⚠️ Why Cache is Disabled
-During testing, we discovered the cache key generation uses only the first 100 characters of prompts:
-```javascript
-_generateCacheKey(prompt, options) {
-    const keyData = {
-        prompt: prompt.substring(0, 100), // PROBLEMATIC - Too short
-        temperature: options.temperature || 0.3,
-        type: this._detectExerciseType(prompt)
-    };
-    return JSON.stringify(keyData);
-}
-```
-
-**Problems identified:**
-- ❌ Different questions with similar beginnings share cache entries
-- ❌ False consistency in test results (all 100% same scores)
-- ❌ Masks real AI variance and bugs
-- ❌ Wrong answers getting cached as correct answers
-
-### 🔧 How to Re-enable Cache
-
-**Option 1: Simple Re-activation (Testing Complete)**
-```javascript
-// In src/DRS/services/IAEngine.js, lines 165-170
-// Uncomment these lines:
-const cacheKey = this._generateCacheKey(prompt, options);
-if (this.cache.has(cacheKey)) {
-    this.stats.cacheHits++;
-    this._log('📦 Cache hit for educational validation');
-    return this.cache.get(cacheKey);
-}
-```
-
-**Option 2: Improved Cache Key (Recommended)**
-```javascript
-_generateCacheKey(prompt, options) {
-    const keyData = {
-        prompt: prompt.substring(0, 200), // Increase from 100 to 200
-        temperature: options.temperature || 0.3,
-        type: this._detectExerciseType(prompt),
-        // Add more distinguishing factors:
-        language: options.language,
-        exerciseType: options.exerciseType,
-        contentHash: this._hashContent(prompt) // Full content hash
-    };
-    return JSON.stringify(keyData);
-}
-```
-
-**Option 3: Selective Caching**
-```javascript
-// Only cache if prompt is long enough and specific enough
-if (prompt.length > 150 && options.exerciseType) {
-    const cacheKey = this._generateCacheKey(prompt, options);
-    if (this.cache.has(cacheKey)) {
-        // ... cache logic
-    }
-}
-```
-
-### 🎯 Production Recommendations
-
-**For Production Use:**
-1. **Re-enable cache** after comprehensive testing
-2. **Improve cache key** to include more context
-3. **Monitor cache hit rates** (target: 30-50%)
-4. **Set cache expiration** (e.g., 24 hours)
-5. **Cache size limits** (currently: 1000 entries)
-
-**For Development/Testing:**
-1. **Keep cache disabled** during AI prompt development
-2. **Enable only for performance testing**
-3. **Clear cache between test suites**
-
-### 📊 Cache Performance Benefits
-When properly configured:
-- **Cost Reduction**: 40-60% fewer API calls
-- **Speed Improvement**: Instant responses for repeated content
-- **Rate Limiting**: Avoids API limits during peak usage
-- **Reliability**: Reduces dependency on external AI services
-
-### 🔍 Cache Monitoring
-Access cache statistics:
-```javascript
-window.app.getCore().iaEngine.stats.cacheHits
-window.app.getCore().iaEngine.cache.size
-```
-
----
-
-## 🧪 AI Testing Results
-
-### Final Validation (Without Cache)
-**Test Date**: December 2024
-**Scoring Accuracy**: 100% (4/4 test cases passed)
-
-**Test Results:**
-- ✅ **Wrong Science Answer**: 0 points (expected: 0-30)
-- ✅ **Correct History Answer**: 90 points (expected: 70-100)
-- ✅ **Wrong Translation**: 0 points (expected: 0-30)
-- ✅ **Correct Spanish Translation**: 100 points (expected: 70-100)
-
-**Bug Fixed**: Translation prompt now correctly uses `context.toLang` instead of hardcoded languages.
-
-**System Status**: ✅ **PRODUCTION READY**
-- Real AI scoring (no mock responses)
-- Strict scoring logic enforced
-- Multi-language support working
-- OpenAI → DeepSeek fallback functional
-
----
-
-## 🧠 Intelligent Content Dependency System
-
-### Smart Vocabulary Prerequisites
-
-**NEW APPROACH**: Instead of forcing vocabulary based on arbitrary mastery percentages, the system now uses **intelligent content dependency analysis**.
-
-#### 🎯 **Core Logic**
-
-**Before executing any exercise, analyze the next content:**
-
-1. **Content Analysis** - Extract all words from upcoming content (phrases, texts, dialogs)
-2. **Dependency Check** - For each word in content:
-   - Is it in our vocabulary module list?
-   - Is it already discovered by the user?
-3. **Smart Decision** - Only force vocabulary if content has undiscovered words that are in our vocabulary list
-4. **Targeted Learning** - Focus vocabulary practice on words actually needed for next content
-
-#### 🏗️ **Implementation Architecture**
-
-**ContentDependencyAnalyzer Class:**
-```javascript
-class ContentDependencyAnalyzer {
-    analyzeContentDependencies(nextContent, vocabularyModule) {
-        const wordsInContent = this.extractWordsFromContent(nextContent);
-        const vocabularyWords = vocabularyModule.getVocabularyWords();
-        const missingWords = this.findMissingWords(wordsInContent, vocabularyWords);
-
-        return {
-            hasUnmetDependencies: missingWords.length > 0,
-            missingWords: missingWords,
-            totalWordsInContent: wordsInContent.length
-        };
-    }
-}
-```
-
-**Smart Override Logic:**
-```javascript
-_shouldUseWordDiscovery(exerciseType, exerciseConfig) {
-    const nextContent = await this.getNextContent(exerciseConfig);
-    const analysis = this.analyzer.analyzeContentDependencies(nextContent, this.vocabularyModule);
-
-    if (analysis.hasUnmetDependencies) {
-        window.vocabularyOverrideActive = {
-            originalType: exerciseConfig.type,
-            reason: `Content requires ${analysis.missingWords.length} undiscovered words`,
-            missingWords: analysis.missingWords
-        };
-        return true;
-    }
-    return false;
-}
-```
-
-#### 🎯 **User Experience Impact**
-
-**Before (Dumb System):**
-- "Vocabulary mastery too low (15%), forcing flashcards"
-- User learns random words not related to next content
-- Arbitrary percentage-based decisions
-
-**After (Smart System):**
-- "Next content requires these words: refrigerator, elevator, closet"
-- User learns exactly the words needed for comprehension
-- Content-driven vocabulary acquisition
-
-#### 📊 **Smart Guide Integration**
-
-**Interface Updates:**
-```
-📚 Vocabulary Practice (3 words needed for next content)
-Type: 📚 Vocabulary Practice
-Mode: Adaptive Flashcards
-Why this exercise?
-Next content requires these words: refrigerator, elevator, closet. Learning vocabulary first ensures comprehension.
-```
-
-#### 🔧 **Key Functions**
-
-- `extractWordsFromContent()` - Parse text/phrases/dialogs for vocabulary
-- `findMissingWords()` - Identify vocabulary words that aren't discovered
-- `getNextContent()` - Fetch upcoming exercise content for analysis
-- `updateVocabularyOverrideUI()` - Smart Guide interface adaptation
-
-#### ✅ **Benefits**
-
-- **Targeted Learning** - Only learn words actually needed
-- **Context-Driven** - Vocabulary tied to real content usage
-- **Efficient Progress** - No time wasted on irrelevant words
-- **Better Retention** - Words learned in context of upcoming usage
-- **Smart Adaptation** - UI accurately reflects what's happening
-
-**Status**: ✅ **DESIGN READY FOR IMPLEMENTATION**
-
----
-
-## 📊 ROBUST PROGRESS SYSTEM - Ultra-Strict Architecture
-
-### 🎯 Core Philosophy
-
-**FUNDAMENTAL RULE**: Every piece of content is a trackable progress item with strict validation and type safety.
-
-### 🏗️ Pedagogical Flow (NON-NEGOTIABLE)
-
-```
-1. DISCOVERY → 2. MASTERY → 3. APPLICATION
-   (passive)      (active)       (context)
-```
-
-**Flow Rules:**
-- ❌ **NO Flashcards on undiscovered words** - Must discover first
-- ❌ **NO Text exercises on unmastered vocabulary** - Must master first
-- ✅ **Always check prerequisites before ANY exercise**
-- ✅ **Form vocabulary lists on-the-fly** from next exercise content
-
-### 📦 Progress Item System
-
-#### **Item Types & Weights**
-
-Each content piece = 1 or more progress items with defined weights:
-
-| Type | Weight | Description | Prerequisites |
-|------|--------|-------------|---------------|
-| **vocabulary-discovery** | 1 | Passive exposure to new word | None |
-| **vocabulary-mastery** | 1 | Active flashcard practice | Must be discovered |
-| **phrase** | 6 | Phrase comprehension (3x vocab) | Vocabulary mastered |
-| **dialog** | 12 | Dialog comprehension (6x vocab, complex) | Vocabulary mastered |
-| **text** | 15 | Full text analysis (7.5x vocab, most complex) | Vocabulary mastered |
-| **audio** | 12 | Audio comprehension (6x vocab) | Vocabulary mastered |
-| **image** | 6 | Image description (3x vocab) | Vocabulary discovered |
-| **grammar** | 6 | Grammar rules (3x vocab) | Vocabulary discovered |
-
-**Total for 1 vocabulary word** = 2 points (1 discovery + 1 mastery)
-
-#### **Strict Interface Contract**
-
-```javascript
-// ALL progress items MUST implement this interface
-class ProgressItemInterface {
-    validate()           // ⚠️ REQUIRED - Validate item data
-    serialize()          // ⚠️ REQUIRED - Convert to JSON
-    getWeight()          // ⚠️ REQUIRED - Return item weight
-    canComplete(state)   // ⚠️ REQUIRED - Check prerequisites
-}
-```
-
-**Missing implementation = FATAL ERROR** (red screen, app refuses to start)
-
-### 🔥 Ultra-Strict Validation System
-
-#### **Runtime Checks**
-
-**At Application Startup:**
-1. Validate ALL item implementations
-2. Check ALL methods are implemented
-3. Verify weight calculations
-4. Test prerequisite logic
-
-**If ANY validation fails:**
-- 🔴 **Full-screen red error overlay**
-- 🔊 **Alert sound** (dev mode)
-- 📳 **Screen shake animation**
-- 🚨 **Giant error message with:**
-  - Class name
-  - Missing method name
-  - Stack trace
-- ❌ **Application REFUSES to start**
-
-#### **Error Display Example**
-
-```
-┌─────────────────────────────────────────────┐
-│                                             │
-│           🔥 FATAL ERROR 🔥                │
-│                                             │
-│      Implementation Missing                 │
-│                                             │
-│  Class: VocabularyMasteryItem              │
-│  Missing Method: canComplete()             │
-│                                             │
-│  ❌ MUST implement all interface methods   │
-│                                             │
-│     [ Dismiss (Fix Required!) ]            │
-│                                             │
-└─────────────────────────────────────────────┘
-```
-
-**Impossible to ignore. Impossible to skip. Forces correct implementation.**
-
-### 📈 Progress Calculation
-
-#### **Chapter Analysis**
-
-When loading a chapter, the system:
-
-1. **Scans ALL content** (vocabulary, phrases, dialogs, texts, etc.)
-2. **Creates progress items** for each piece
-3. **Calculates total weight** (sum of all item weights)
-4. **Stores item registry** for tracking
-
-**Example Chapter:**
-- 171 vocabulary words → 342 points (171×2: discovery + mastery)
-- 75 phrases → 450 points (75×6)
-- 6 dialogs → 72 points (6×12)
-- 3 lessons → 45 points (3×15)
-- **TOTAL: 909 points**
-
-#### **Progress Calculation**
-
-```javascript
-percentage = (completedWeight / totalWeight) × 100
-
-Example:
-- Discovered 50 words = 50 points
-- Mastered 20 words = 20 points
-- Completed 3 phrases = 18 points (3×6)
-- Completed 1 dialog = 12 points
-- Total completed = 100 points
-- Progress = (100 / 909) × 100 = 11%
-```
-
-#### **Breakdown Display**
-
-```javascript
-{
-  percentage: 11,
-  completedWeight: 100,
-  totalWeight: 909,
-  breakdown: {
-    'vocabulary-discovery': { count: 50, weight: 50 },
-    'vocabulary-mastery': { count: 20, weight: 20 },
-    'phrase': { count: 3, weight: 18 },
-    'dialog': { count: 1, weight: 12 }
-  }
-}
-```
-
-### 🎯 On-The-Fly Vocabulary Formation
-
-**OLD (Wrong):** Pre-load all 171 words for flashcards
-
-**NEW (Correct):**
-1. **Analyze next exercise** (e.g., Dialog #3)
-2. **Extract words used** in that specific dialog
-3. **Check user's status** for those words
-4. **Form targeted list** of only needed words
-5. **Force discovery/mastery** for just those words
-
-**Example:**
-```javascript
-// Next exercise: Dialog "Academic Conference"
-// Words in dialog: methodology, hypothesis, analysis, paradigm, framework
-
-// User status check:
-// - methodology: never seen → Discovery needed
-// - hypothesis: discovered, not mastered → Mastery needed
-// - analysis: mastered → Skip
-// - paradigm: never seen → Discovery needed
-// - framework: discovered, not mastered → Mastery needed
-
-// Smart system creates:
-// 1. Discovery module: [methodology, paradigm] (2 words)
-// 2. Mastery module: [hypothesis, framework] (2 words)
-// 3. Then allow dialog exercise
-```
-
-### 🔧 Implementation Components
-
-#### **Required Classes**
-
-1. **ProgressItemInterface** - Abstract base with strict validation
-2. **StrictInterface** - Enforcement mechanism with visual errors
-3. **ContentProgressAnalyzer** - Scans content, creates items, calculates total
-4. **ProgressTracker** - Manages state, marks completion, saves progress
-5. **ImplementationValidator** - Runtime validation at startup
-
-#### **Concrete Item Implementations**
-
-- VocabularyDiscoveryItem
-- VocabularyMasteryItem
-- PhraseItem
-- DialogItem
-- TextItem
-- AudioItem
-- ImageItem
-- GrammarItem
-
-**Each MUST implement all 4 interface methods or app fails to start**
-
-### ✅ Validation Checklist
-
-**Before ANY exercise can run:**
-- [ ] Prerequisites analyzed for next specific content
-- [ ] Missing words identified
-- [ ] Discovery forced for never-seen words
-- [ ] Mastery forced for seen-but-not-mastered words
-- [ ] Progress item created with correct weight
-- [ ] Completion properly tracked and saved
-- [ ] Total progress recalculated
-
-**If ANY step fails → Clear error message, app stops gracefully**
-
-### 🎨 UI Integration
-
-**Progress Display:**
-```
-Chapter Progress: 11% (100/909 points)
-
-✅ Vocabulary Discovery: 50/171 words (50pts)
-✅ Vocabulary Mastery: 20/171 words (20pts)
-✅ Phrases: 3/75 (18pts)
-✅ Dialogs: 1/6 (12pts)
-⬜ Texts: 0/3 (0/45pts)
-```
-
-**Smart Guide Updates:**
-```
-🔍 Analyzing next exercise: Dialog "Academic Conference"
-📚 4 words needed (2 discovery, 2 mastery)
-🎯 Starting Vocabulary Discovery for: methodology, paradigm
-```
-
-### 🚨 Error Prevention
-
-**Compile-Time (Startup):**
-- Interface validation
-- Method implementation checks
-- Weight configuration validation
-
-**Runtime:**
-- Prerequisite enforcement
-- State consistency checks
-- Progress calculation validation
-
-**Visual Feedback:**
-- Red screen for missing implementations
-- Clear prerequisite errors
-- Progress breakdown always visible
-
----
-
-**Status**: 📝 **DOCUMENTED - READY FOR IMPLEMENTATION**
-
----
-
-## 🔒 STRICT INTERFACE SYSTEM - C++ Style Contracts
-
-### 🎯 Philosophy: Contract-Driven Architecture
-
-**Like C++ header files (.h)**, we enforce strict interfaces that MUST be implemented. Any missing method = **RED SCREEN ERROR** at startup.
-
-### 📦 Interface Hierarchy
-
-```
-StrictInterface (base)
-├── ProgressItemInterface           # For progress tracking items
-│   ├── VocabularyDiscoveryItem
-│   ├── VocabularyMasteryItem
-│   └── ContentProgressItems (Phrase, Dialog, Text, etc.)
-│
-├── ProgressSystemInterface         # For progress systems
-│   ├── ProgressTracker
-│   └── PrerequisiteEngine
-│
-└── DRSExerciseInterface           # For exercise modules
-    ├── VocabularyModule
-    ├── TextAnalysisModule
-    ├── GrammarAnalysisModule
-    ├── TranslationModule
-    └── OpenResponseModule
-```
-
-### 🏗️ 1. **StrictInterface** (Base Class)
-
-**Location**: `src/DRS/interfaces/StrictInterface.js`
-
-**Purpose**: Ultra-strict base class with visual error enforcement
-
-**Features**:
-- ✅ Validates implementation at construction
-- ✅ Full-screen red error overlay if method missing
-- ✅ Sound alert in dev mode
-- ✅ Screen shake animation
-- ✅ Impossible to ignore - forces correct implementation
-
-**Error Display**:
-```
-┌─────────────────────────────────────────────┐
-│                                             │
-│           🔥 FATAL ERROR 🔥                │
-│                                             │
-│      Implementation Missing                 │
-│                                             │
-│  Class: VocabularyModule                   │
-│  Missing Method: validate()                │
-│                                             │
-│  ❌ MUST implement all interface methods   │
-│                                             │
-│     [ DISMISS (Fix Required!) ]            │
-│                                             │
-└─────────────────────────────────────────────┘
-```
-
-### 🎯 2. **ProgressItemInterface**
-
-**Location**: `src/DRS/interfaces/ProgressItemInterface.js`
-
-**Purpose**: Contract for all progress tracking items
-
-**Required Methods** (4):
-```javascript
-validate()           // Validate item data
-serialize()          // Convert to JSON
-getWeight()          // Return item weight for progress calculation
-canComplete(state)   // Check prerequisites
-```
-
-**Implementations**:
-- VocabularyDiscoveryItem (1pt)
-- VocabularyMasteryItem (1pt)
-- PhraseItem (6pts)
-- DialogItem (12pts)
-- TextItem (15pts)
-- AudioItem (12pts)
-- ImageItem (6pts)
-- GrammarItem (6pts)
-
-### 🔧 3. **ProgressSystemInterface**
-
-**Location**: `src/DRS/interfaces/ProgressSystemInterface.js`
-
-**Purpose**: Contract for all progress management systems
-
-**Required Methods** (17):
-
-**Vocabulary Tracking:**
-- `markWordDiscovered(word, metadata)`
-- `markWordMastered(word, metadata)`
-- `isWordDiscovered(word)`
-- `isWordMastered(word)`
-
-**Content Tracking:**
-- `markPhraseCompleted(id, metadata)`
-- `markDialogCompleted(id, metadata)`
-- `markTextCompleted(id, metadata)`
-- `markAudioCompleted(id, metadata)`
-- `markImageCompleted(id, metadata)`
-- `markGrammarCompleted(id, metadata)`
-
-**Prerequisites:**
-- `canComplete(itemType, itemId, context)`
-
-**Progress:**
-- `getProgress(chapterId)`
-
-**Persistence:**
-- `saveProgress(bookId, chapterId)`
-- `loadProgress(bookId, chapterId)`
-
-**Utility:**
-- `reset(bookId, chapterId)`
-
-**Implementations**:
-- ProgressTracker - Weight-based progress with items
-- PrerequisiteEngine - Prerequisite checking and mastery tracking
-
-### 🎮 4. **DRSExerciseInterface**
-
-**Location**: `src/DRS/interfaces/DRSExerciseInterface.js`
-
-**Purpose**: Contract for all DRS exercise modules
-
-**Required Methods** (10):
-
-**Lifecycle:**
-- `init(config, content)` - Initialize exercise
-- `render(container)` - Render UI
-- `destroy()` - Clean up
-
-**Exercise Logic:**
-- `validate(userAnswer)` - Validate answer, return { isCorrect, score, feedback, explanation }
-- `getResults()` - Return { score, attempts, timeSpent, completed, details }
-- `handleUserInput(event, data)` - Handle user input
-
-**Progress Tracking:**
-- `markCompleted(results)` - Mark as completed
-- `getProgress()` - Return { percentage, currentStep, totalSteps, itemsCompleted, itemsTotal }
-
-**Metadata:**
-- `getExerciseType()` - Return exercise type string
-- `getExerciseConfig()` - Return { type, difficulty, estimatedTime, prerequisites, metadata }
-
-**Implementations**:
-- VocabularyModule - Flashcard spaced repetition
-- TextAnalysisModule - AI-powered text comprehension
-- GrammarAnalysisModule - AI grammar correction
-- TranslationModule - AI translation validation
-- OpenResponseModule - Free-form AI evaluation
-
-### ✅ 5. **ImplementationValidator**
-
-**Location**: `src/DRS/services/ImplementationValidator.js`
-
-**Purpose**: Validate ALL implementations at application startup
-
-**Validation Phases**:
-
-```javascript
-🔍 VALIDATING DRS IMPLEMENTATIONS...
-
-📦 PART 1: Validating Progress Items...
-  ✅ VocabularyDiscoveryItem - OK
-  ✅ VocabularyMasteryItem - OK
-  ✅ PhraseItem - OK
-  ✅ DialogItem - OK
-  ✅ TextItem - OK
-  ✅ AudioItem - OK
-  ✅ ImageItem - OK
-  ✅ GrammarItem - OK
-
-🔧 PART 2: Validating Progress Systems...
-  ✅ ProgressTracker - OK
-  ✅ PrerequisiteEngine - OK
-
-🎮 PART 3: Validating DRS Exercise Modules...
-  ✅ VocabularyModule - OK
-  ✅ TextAnalysisModule - OK
-  ✅ GrammarAnalysisModule - OK
-  ✅ TranslationModule - OK
-  ✅ OpenResponseModule - OK
-
-✅ ALL DRS IMPLEMENTATIONS VALID
-```
-
-**If ANY validation fails**:
-- 🔴 Full-screen red error
-- 🚫 Application REFUSES to start
-- 📋 Clear error message with missing method name
-- 🔊 Alert sound (dev mode)
-- 📳 Screen shake
-
-### 🎯 Integration with Application.js
-
-**At Startup** (lines 55-62):
-```javascript
-// Validate all progress item implementations (STRICT MODE)
-console.log('🔍 Validating progress item implementations...');
-const { default: ImplementationValidator } = await import('./DRS/services/ImplementationValidator.js');
-const isValid = await ImplementationValidator.validateAll();
-
-if (!isValid) {
-    throw new Error('❌ Implementation validation failed - check console for details');
-}
-```
-
-### 📋 Creating New Implementations
-
-#### **New Progress Item**:
-```javascript
-import ProgressItemInterface from '../interfaces/ProgressItemInterface.js';
-
-class MyCustomItem extends ProgressItemInterface {
-    constructor(id, metadata) {
-        super('my-custom-item', id, metadata);
-    }
-
-    validate() {
-        // MUST implement
-        if (!this.metadata.required) {
-            throw new Error('Missing required data');
-        }
-        return true;
-    }
-
-    serialize() {
-        // MUST implement
-        return {
-            ...this._getBaseSerialization(),
-            customData: this.metadata.custom
-        };
-    }
-
-    getWeight() {
-        // MUST implement
-        return ProgressItemInterface.WEIGHTS['my-custom-item'] || 5;
-    }
-
-    canComplete(userProgress) {
-        // MUST implement
-        return true; // Check prerequisites here
-    }
-}
-```
-
-#### **New Progress System**:
-```javascript
-import ProgressSystemInterface from '../interfaces/ProgressSystemInterface.js';
-
-class MyProgressSystem extends ProgressSystemInterface {
-    constructor() {
-        super('MyProgressSystem');
-    }
-
-    // MUST implement all 17 required methods
-    async markWordDiscovered(word, metadata = {}) { /* ... */ }
-    async markWordMastered(word, metadata = {}) { /* ... */ }
-    isWordDiscovered(word) { /* ... */ }
-    isWordMastered(word) { /* ... */ }
-    // ... 13 more methods
-}
-```
-
-#### **New Exercise Module**:
-```javascript
-import DRSExerciseInterface from '../interfaces/DRSExerciseInterface.js';
-
-class MyExerciseModule extends DRSExerciseInterface {
-    constructor() {
-        super('MyExerciseModule');
-    }
-
-    // MUST implement all 10 required methods
-    async init(config, content) { /* ... */ }
-    async render(container) { /* ... */ }
-    async destroy() { /* ... */ }
-    async validate(userAnswer) { /* ... */ }
-    getResults() { /* ... */ }
-    handleUserInput(event, data) { /* ... */ }
-    async markCompleted(results) { /* ... */ }
-    getProgress() { /* ... */ }
-    getExerciseType() { return 'my-exercise'; }
-    getExerciseConfig() { /* ... */ }
-}
-```
-
-### 🚨 Enforcement Rules
-
-**NON-NEGOTIABLE**:
-1. ❌ **Missing method** → RED SCREEN ERROR → App refuses to start
-2. ❌ **Wrong signature** → Runtime error on call
-3. ❌ **Wrong return format** → Runtime error on usage
-4. ✅ **All methods implemented** → App starts normally
-
-**Validation happens**:
-- ✅ At application startup (before any UI renders)
-- ✅ On module registration
-- ✅ At interface instantiation
-
-**Benefits**:
-- 🛡️ **Impossible to forget implementation** - Visual error forces fix
-- 📋 **Self-documenting** - Interface defines exact contract
-- 🔒 **Type safety** - Like TypeScript interfaces but enforced at runtime
-- 🧪 **Testable** - Can mock interfaces for unit tests
-- 🔄 **Maintainable** - Adding new method = update interface + all implementations get errors
-
----
-
-**Status**: ✅ **INTERFACE SYSTEM IMPLEMENTED**
-
----
-
-**This is a high-quality, maintainable system built for educational software that will scale.**
\ No newline at end of file
+**High-quality, maintainable educational software that scales.**
diff --git a/content/books/ledu.json b/content/books/ledu.json
new file mode 100644
index 0000000..5961d1c
--- /dev/null
+++ b/content/books/ledu.json
@@ -0,0 +1,206 @@
+{
+  "id": "ledu",
+  "name": "乐读 (Lè dú) - Chinese Reading Course",
+  "description": "Comprehensive Chinese reading course designed for intermediate learners focusing on reading comprehension, vocabulary acquisition, and cultural understanding",
+  "difficulty": "intermediate",
+  "language": "zh-CN",
+  "metadata": {
+    "version": "1.0",
+    "created": "2025-10-14",
+    "updated": "2025-10-14",
+    "source": "Jiaotong University Chinese Program",
+    "target_level": "intermediate",
+    "total_estimated_hours": 120,
+    "prerequisites": ["basic-chinese", "hsk-3"],
+    "learning_objectives": [
+      "Master intermediate Chinese vocabulary for daily life contexts",
+      "Develop reading comprehension skills with authentic Chinese texts",
+      "Understand Chinese character structures and radicals",
+      "Practice inferring meaning from context",
+      "Learn Chinese cultural concepts through reading"
+    ],
+    "content_tags": ["chinese", "reading", "vocabulary", "comprehension", "culture"],
+    "total_chapters": 12,
+    "available_chapters": [
+      "ledu-chapter1",
+      "ledu-chapter2",
+      "ledu-chapter3",
+      "ledu-chapter4",
+      "ledu-chapter5",
+      "ledu-chapter6",
+      "ledu-chapter7",
+      "ledu-chapter8",
+      "ledu-chapter9",
+      "ledu-chapter10",
+      "ledu-chapter11",
+      "ledu-chapter12"
+    ],
+    "completion_criteria": {
+      "overall_progress": 85,
+      "chapters_completed": 12,
+      "vocabulary_mastery": 90,
+      "comprehension_score": 80
+    }
+  },
+  "chapters": [
+    {
+      "id": "ledu-chapter1",
+      "chapter_number": "1",
+      "name": "民以食为天 (Food is Heaven for the People)",
+      "description": "Introduction to Chinese food culture and dietary vocabulary",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "prerequisites": ["hsk-3"],
+      "learning_objectives": [
+        "Master food-related vocabulary",
+        "Understand Chinese dining etiquette",
+        "Learn to infer character meanings from radicals",
+        "Practice reading authentic texts about Chinese cuisine"
+      ],
+      "vocabulary_count": 45,
+      "phrases_count": 20,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter2",
+      "chapter_number": "2",
+      "name": "Chapter 2",
+      "description": "Second chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 40,
+      "phrases_count": 18,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter3",
+      "chapter_number": "3",
+      "name": "生命在于运动 (Life Lies in Movement)",
+      "description": "Comprehensive chapter on sports, fitness, and healthy lifestyle with focus on forming exercise habits",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "prerequisites": ["ledu-chapter1", "ledu-chapter2"],
+      "learning_objectives": [
+        "Master 30+ sports and fitness vocabulary terms",
+        "Understand strategies for building exercise habits",
+        "Learn about ping-pong history and Chinese sports culture",
+        "Practice reading comprehension with authentic texts",
+        "Develop skills in contextual vocabulary inference"
+      ],
+      "vocabulary_count": 35,
+      "phrases_count": 15,
+      "texts_count": 3,
+      "exercises_count": 20
+    },
+    {
+      "id": "ledu-chapter4",
+      "chapter_number": "4",
+      "name": "Chapter 4",
+      "description": "Fourth chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 38,
+      "phrases_count": 17,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter5",
+      "chapter_number": "5",
+      "name": "Chapter 5",
+      "description": "Fifth chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 40,
+      "phrases_count": 18,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter6",
+      "chapter_number": "6",
+      "name": "Chapter 6",
+      "description": "Sixth chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 42,
+      "phrases_count": 19,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter7",
+      "chapter_number": "7",
+      "name": "Chapter 7",
+      "description": "Seventh chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 40,
+      "phrases_count": 18,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter8",
+      "chapter_number": "8",
+      "name": "Chapter 8",
+      "description": "Eighth chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 38,
+      "phrases_count": 17,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter9",
+      "chapter_number": "9",
+      "name": "Chapter 9",
+      "description": "Ninth chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 40,
+      "phrases_count": 18,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter10",
+      "chapter_number": "10",
+      "name": "Chapter 10",
+      "description": "Tenth chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 42,
+      "phrases_count": 19,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter11",
+      "chapter_number": "11",
+      "name": "Chapter 11",
+      "description": "Eleventh chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 40,
+      "phrases_count": 18,
+      "texts_count": 3,
+      "exercises_count": 15
+    },
+    {
+      "id": "ledu-chapter12",
+      "chapter_number": "12",
+      "name": "Chapter 12",
+      "description": "Twelfth chapter of LEDU reading course",
+      "estimated_hours": 10,
+      "difficulty": "intermediate",
+      "vocabulary_count": 38,
+      "phrases_count": 17,
+      "texts_count": 3,
+      "exercises_count": 15
+    }
+  ]
+}
diff --git a/content/chapters/ledu-chapter1.json b/content/chapters/ledu-chapter1.json
new file mode 100644
index 0000000..bff380e
--- /dev/null
+++ b/content/chapters/ledu-chapter1.json
@@ -0,0 +1,548 @@
+{
+  "id": "ledu-chapter1",
+  "book_id": "ledu",
+  "name": "民以食为天 (Food is Heaven for the People)",
+  "description": "Introduction to Chinese food culture, dining etiquette, and dietary vocabulary. Explores the importance of food in Chinese culture and regional taste preferences.",
+  "difficulty": "intermediate",
+  "language": "zh-CN",
+  "chapter_number": "1",
+  "metadata": {
+    "version": "1.0",
+    "created": "2025-10-14",
+    "updated": "2025-10-14",
+    "source": "LEDU Textbook - Jiaotong University",
+    "target_level": "intermediate",
+    "estimated_hours": 10,
+    "prerequisites": ["hsk-3"],
+    "learning_objectives": [
+      "Master 45+ food and dining vocabulary terms",
+      "Understand Chinese dining etiquette and table manners",
+      "Learn about regional taste differences in China",
+      "Practice character inference from radicals",
+      "Develop reading comprehension skills with authentic texts"
+    ],
+    "content_tags": ["food", "culture", "etiquette", "regional-cuisine", "chinese-culture"],
+    "completion_criteria": {
+      "vocabulary_mastery": 90,
+      "comprehension_score": 80,
+      "exercises_completed": 15
+    }
+  },
+  "vocabulary": {
+    "食": {
+      "pronunciation": "shí",
+      "type": "morpheme",
+      "user_language": "food, to eat",
+      "examples": ["饮食", "甜食", "肉食", "食堂"],
+      "notes": "Pictographic character representing food in a container. Usually used as morpheme."
+    },
+    "重": {
+      "pronunciation": "zhòng",
+      "type": "adjective/verb",
+      "user_language": "heavy; important; to attach importance to",
+      "examples": ["体重", "严重", "重要", "敬重"]
+    },
+    "嘴": {
+      "pronunciation": "zuǐ",
+      "type": "noun",
+      "user_language": "mouth",
+      "examples": ["一张嘴", "张开嘴", "烫嘴"]
+    },
+    "脑": {
+      "pronunciation": "nǎo",
+      "type": "noun",
+      "user_language": "brain",
+      "examples": ["大脑", "脑子"]
+    },
+    "重视": {
+      "pronunciation": "zhòngshì",
+      "type": "verb",
+      "user_language": "to attach importance to, to value",
+      "examples": ["重视健康", "重视学习", "对…很/不重视"]
+    },
+    "营养": {
+      "pronunciation": "yíngyǎng",
+      "type": "noun",
+      "user_language": "nutrition",
+      "examples": ["有营养", "营养丰富"]
+    },
+    "文化": {
+      "pronunciation": "wénhuà",
+      "type": "noun",
+      "user_language": "culture",
+      "examples": ["饮食文化", "传统文化"]
+    },
+    "丰富": {
+      "pronunciation": "fēngfù",
+      "type": "adjective/verb",
+      "user_language": "rich, abundant; to enrich",
+      "examples": ["营养丰富", "丰富生活"]
+    },
+    "味道": {
+      "pronunciation": "wèidao",
+      "type": "noun",
+      "user_language": "taste, flavor",
+      "examples": ["味道鲜美", "品尝味道"]
+    },
+    "麻辣烫": {
+      "pronunciation": "málàtàng",
+      "type": "noun",
+      "user_language": "spicy hot pot"
+    },
+    "麻婆豆腐": {
+      "pronunciation": "mápó dòufu",
+      "type": "noun",
+      "user_language": "Mapo tofu (tofu in spicy sauce)"
+    },
+    "适合": {
+      "pronunciation": "shìhé",
+      "type": "verb",
+      "user_language": "to suit, to be suitable for",
+      "examples": ["这种颜色不适合我", "他很适合做这个工作"]
+    },
+    "满": {
+      "pronunciation": "mǎn",
+      "type": "adjective",
+      "user_language": "full, complete",
+      "examples": ["满桌", "坐满", "满心欢喜"]
+    },
+    "四川": {
+      "pronunciation": "Sichuān",
+      "type": "proper noun",
+      "user_language": "Sichuan (province of China)"
+    },
+    "历史": {
+      "pronunciation": "lishǐ",
+      "type": "noun",
+      "user_language": "history"
+    },
+    "规矩": {
+      "pronunciation": "guīju",
+      "type": "noun",
+      "user_language": "rule, norm, convention"
+    },
+    "安排": {
+      "pronunciation": "ānpái",
+      "type": "verb",
+      "user_language": "to arrange, to organize"
+    },
+    "敲": {
+      "pronunciation": "qiāo",
+      "type": "verb",
+      "user_language": "to knock, to tap"
+    },
+    "竖": {
+      "pronunciation": "shù",
+      "type": "adjective",
+      "user_language": "vertical, upright"
+    },
+    "礼貌": {
+      "pronunciation": "lǐmào",
+      "type": "adjective",
+      "user_language": "polite, courteous"
+    },
+    "倒": {
+      "pronunciation": "dào",
+      "type": "verb",
+      "user_language": "to pour"
+    },
+    "尊重": {
+      "pronunciation": "zūnzhòng",
+      "type": "verb",
+      "user_language": "to respect, to esteem"
+    },
+    "敬酒": {
+      "pronunciation": "jìng jiǔ",
+      "type": "verb",
+      "user_language": "to propose a toast"
+    },
+    "但": {
+      "pronunciation": "dàn",
+      "type": "conjunction",
+      "user_language": "but (written language)",
+      "examples": ["这家饭馆不大，但很有名", "这份工作比较辛苦，但我很喜欢"],
+      "notes": "Written Chinese, same as 但是"
+    },
+    "时": {
+      "pronunciation": "shí",
+      "type": "noun",
+      "user_language": "time, moment (written language)",
+      "examples": ["他看书时喜欢听音乐", "工作时他很认真"],
+      "notes": "Written Chinese, means '……的时候'"
+    },
+    "讲究": {
+      "pronunciation": "jiǎngju",
+      "type": "verb",
+      "user_language": "to be particular about, to pay attention to"
+    },
+    "色": {
+      "pronunciation": "sè",
+      "type": "noun",
+      "user_language": "color"
+    },
+    "香": {
+      "pronunciation": "xiāng",
+      "type": "adjective",
+      "user_language": "fragrant, aromatic"
+    },
+    "形": {
+      "pronunciation": "xíng",
+      "type": "noun",
+      "user_language": "shape, form"
+    },
+    "意": {
+      "pronunciation": "yì",
+      "type": "noun",
+      "user_language": "meaning, significance"
+    },
+    "颜色": {
+      "pronunciation": "yánsè",
+      "type": "noun",
+      "user_language": "color"
+    },
+    "漂亮": {
+      "pronunciation": "piàoliang",
+      "type": "adjective",
+      "user_language": "beautiful, pretty"
+    },
+    "口感": {
+      "pronunciation": "kǒugǎn",
+      "type": "noun",
+      "user_language": "taste, mouthfeel"
+    },
+    "样子": {
+      "pronunciation": "yàngzi",
+      "type": "noun",
+      "user_language": "appearance, look"
+    },
+    "意义": {
+      "pronunciation": "yìyì",
+      "type": "noun",
+      "user_language": "meaning, significance"
+    },
+    "以前": {
+      "pronunciation": "yǐqián",
+      "type": "noun",
+      "user_language": "before, previously"
+    },
+    "甜": {
+      "pronunciation": "tián",
+      "type": "adjective",
+      "user_language": "sweet"
+    },
+    "咸": {
+      "pronunciation": "xián",
+      "type": "adjective",
+      "user_language": "salty"
+    },
+    "辣": {
+      "pronunciation": "là",
+      "type": "adjective",
+      "user_language": "spicy"
+    },
+    "酸": {
+      "pronunciation": "suān",
+      "type": "adjective",
+      "user_language": "sour"
+    },
+    "各地": {
+      "pronunciation": "gèdì",
+      "type": "noun",
+      "user_language": "various places, everywhere"
+    },
+    "爱上": {
+      "pronunciation": "àishang",
+      "type": "verb",
+      "user_language": "to fall in love with"
+    },
+    "辣椒": {
+      "pronunciation": "làjiāo",
+      "type": "noun",
+      "user_language": "chili pepper"
+    },
+    "离不开": {
+      "pronunciation": "lí bu kāi",
+      "type": "verb",
+      "user_language": "can't do without"
+    },
+    "麻": {
+      "pronunciation": "má",
+      "type": "adjective",
+      "user_language": "numbing (Sichuan pepper sensation)"
+    },
+    "最爱": {
+      "pronunciation": "zuì'ài",
+      "type": "noun",
+      "user_language": "favorite"
+    },
+    "火锅": {
+      "pronunciation": "huǒguō",
+      "type": "noun",
+      "user_language": "hot pot"
+    },
+    "口味": {
+      "pronunciation": "kǒuwèi",
+      "type": "noun",
+      "user_language": "taste preference"
+    },
+    "温暖": {
+      "pronunciation": "wēnnuǎn",
+      "type": "adjective",
+      "user_language": "warm"
+    },
+    "快乐": {
+      "pronunciation": "kuàilè",
+      "type": "adjective",
+      "user_language": "happy"
+    },
+    "食欲": {
+      "pronunciation": "shíyù",
+      "type": "noun",
+      "user_language": "appetite"
+    },
+    "喜爱": {
+      "pronunciation": "xǐ'ài",
+      "type": "verb",
+      "user_language": "to like, to love"
+    },
+    "古人": {
+      "pronunciation": "gǔrén",
+      "type": "noun",
+      "user_language": "ancient people, ancestors"
+    },
+    "事情": {
+      "pronunciation": "shìqing",
+      "type": "noun",
+      "user_language": "matter, thing, affair"
+    },
+    "年长": {
+      "pronunciation": "niánzhǎng",
+      "type": "adjective",
+      "user_language": "elderly, senior"
+    },
+    "入座": {
+      "pronunciation": "rùzuò",
+      "type": "verb",
+      "user_language": "to take a seat"
+    },
+    "主人": {
+      "pronunciation": "zhǔrén",
+      "type": "noun",
+      "user_language": "host"
+    },
+    "动筷子": {
+      "pronunciation": "dòng kuàizi",
+      "type": "verb phrase",
+      "user_language": "to start eating (lit. move chopsticks)"
+    },
+    "品尝": {
+      "pronunciation": "pǐncháng",
+      "type": "verb",
+      "user_language": "to taste"
+    },
+    "夹菜": {
+      "pronunciation": "jiācài",
+      "type": "verb",
+      "user_language": "to pick up food with chopsticks"
+    },
+    "盘子": {
+      "pronunciation": "pánzi",
+      "type": "noun",
+      "user_language": "plate"
+    },
+    "热情": {
+      "pronunciation": "rèqíng",
+      "type": "noun",
+      "user_language": "enthusiasm, warmth"
+    },
+    "碗": {
+      "pronunciation": "wǎn",
+      "type": "noun",
+      "user_language": "bowl"
+    },
+    "插": {
+      "pronunciation": "chā",
+      "type": "verb",
+      "user_language": "to insert, to stick in"
+    },
+    "米饭": {
+      "pronunciation": "mǐfàn",
+      "type": "noun",
+      "user_language": "rice"
+    },
+    "同样": {
+      "pronunciation": "tóngyàng",
+      "type": "adverb",
+      "user_language": "likewise, similarly"
+    },
+    "长辈": {
+      "pronunciation": "zhǎngbèi",
+      "type": "noun",
+      "user_language": "elder, senior"
+    },
+    "烫手": {
+      "pronunciation": "tàng shǒu",
+      "type": "verb phrase",
+      "user_language": "to burn one's hand"
+    },
+    "酒": {
+      "pronunciation": "jiǔ",
+      "type": "noun",
+      "user_language": "alcohol, wine"
+    },
+    "友情": {
+      "pronunciation": "yǒuqíng",
+      "type": "noun",
+      "user_language": "friendship"
+    },
+    "双手": {
+      "pronunciation": "shuāngshǒu",
+      "type": "noun",
+      "user_language": "both hands"
+    },
+    "杯子": {
+      "pronunciation": "bēizi",
+      "type": "noun",
+      "user_language": "cup, glass"
+    },
+    "对方": {
+      "pronunciation": "duìfāng",
+      "type": "noun",
+      "user_language": "the other party"
+    },
+    "吃饱": {
+      "pronunciation": "chī bǎo",
+      "type": "verb",
+      "user_language": "to eat one's fill"
+    },
+    "感谢": {
+      "pronunciation": "gǎnxiè",
+      "type": "verb",
+      "user_language": "to thank"
+    }
+  },
+  "grammar": {
+    "因此-therefore": {
+      "title": "……，因此…… - therefore, consequently",
+      "pattern": "Cause/Reason + 因此 + Result/Consequence",
+      "explanation": "Used to express cause and effect relationship. More formal than 所以.",
+      "examples": [
+        {
+          "chinese": "这家饭馆很有特色，因此生意特别火。",
+          "pronunciation": "Zhè jiā fànguǎn hěn yǒu tèsè, yīncǐ shēngyì tèbié huǒ.",
+          "translation": "This restaurant has specialties, therefore the business is very good."
+        },
+        {
+          "chinese": "这个牌子的饮料口感很好，因此很受年轻人欢迎。",
+          "pronunciation": "Zhège páizi de yǐnliào kǒugǎn hěn hǎo, yīncǐ hěn shòu niánqīngrén huānyíng.",
+          "translation": "This brand of beverage has a good taste, therefore it's very popular among young people."
+        }
+      ]
+    },
+    "但-written": {
+      "title": "但 (dàn) - but (written language)",
+      "explanation": "Used in written Chinese to mean '但是' (but). More formal and concise.",
+      "examples": [
+        {
+          "chinese": "这家饭馆不大，但很有名。",
+          "pronunciation": "Zhè jiā fànguǎn bù dà, dàn hěn yǒumíng.",
+          "translation": "This restaurant is not big, but it's very famous."
+        }
+      ]
+    },
+    "时-written": {
+      "title": "时 (shí) - when, at the time of (written language)",
+      "explanation": "Used in written Chinese to mean '……的时候' (when, at the time of).",
+      "examples": [
+        {
+          "chinese": "他看书时喜欢听音乐。",
+          "pronunciation": "Tā kàn shū shí xǐhuan tīng yīnyuè.",
+          "translation": "When he reads, he likes listening to music."
+        }
+      ]
+    }
+  },
+  "texts": [
+    {
+      "id": "main-text",
+      "title": "中国人用\"嘴\"吃饭 (Chinese People Eat with Their 'Mouth')",
+      "type": "main",
+      "content": "有人说：\"外国人用'脑'吃饭，中国人用'嘴'吃饭。\"外国人比较重视营养，吃什么、怎么吃首先想的是要有营养；中国人讲究菜要色、香、味、形、意都好。中华饮食文化非常丰富，一道菜要颜色漂亮、味道香、口感好、样子好看，还要有美好的意义。\n\n色、香、味、形、意中，味是第一位的。以前中国有句话说：\"南甜北咸，东辣西酸。\"意思是各地的人们各有所爱。而现在有越来越多的人爱上了辣，可以说是无辣不欢。其实辣椒来到中国还不到400年，但现在很多年轻人已经离不开辣了。四川菜又麻又辣，是很多年轻人的最爱。川菜馆在很多地方都很受人们的欢迎，很多人都爱吃麻辣火锅、麻辣烫和麻婆豆腐。\n\n为什么辣更适合年轻人的口味呢？辣味儿能让人感到温暖和快乐，而且红红的辣椒看着就让人满心欢喜，很有食欲，因此更受年轻人喜爱。",
+      "wordCount": 334,
+      "questions": [
+        {
+          "question": "中国菜的特点是什么？",
+          "type": "open",
+          "answer": "色、香、味、形、意都好"
+        },
+        {
+          "question": "现代中国年轻人最喜欢什么口味？原因是什么？",
+          "type": "open",
+          "answer": "辣。因为辣味能让人感到温暖和快乐，红辣椒让人满心欢喜，很有食欲"
+        },
+        {
+          "question": "中国人认为，菜有没有营养没关系。",
+          "type": "true_false",
+          "answer": "错"
+        },
+        {
+          "question": "很多年轻人特别喜欢吃川菜。",
+          "type": "true_false",
+          "answer": "对"
+        },
+        {
+          "question": "辣椒最早产自中国。",
+          "type": "true_false",
+          "answer": "错"
+        }
+      ]
+    },
+    {
+      "id": "etiquette-text",
+      "title": "中国人吃饭的规矩 (Chinese Dining Etiquette)",
+      "type": "extensive",
+      "content": "中国古人说：\"民以食为天。\"对人们来说，吃饭是最重要的事情。中国有五千多年的历史，有丰富的饮食文化，吃饭时也就有了很多规矩，比如说：\n\n规矩一：很多人一起吃饭时，先请客人或者最年长的人入座，客人一般会等主人安排后再入座。\n\n规矩二：开始吃饭时，请客人或者最年长的人先动筷子；每上一道菜，都要请客人或者最年长的人先品尝。\n\n规矩三：有时主人会为客人夹菜，放在客人的盘子里，这是对客人的热情。\n\n规矩四：吃饭时不能用筷子敲碗、盘子；筷子也不可以竖着插在米饭里，这是不礼貌的。\n\n规矩五：\"食不言\"，吃东西时不讲话；同样，看到别人嘴里有食物，也不要去跟人讲话。\n\n规矩六：年轻人为客人或者长辈倒茶、倒酒。\n\n规矩七：给人倒茶时，只倒七分满，还有三分是对客人的热情，而且也不会烫手；但倒酒时，一般要倒满，意思是满满的尊重和友情。\n\n规矩八：年轻人向年长的人敬酒时，一般双手拿杯子，杯子要拿得比对方低一点儿，这是对年长的人的尊重；看到别人正在夹菜，先不要敬酒。\n\n规矩九：慢慢地品尝每一道菜，如果菜只上了一半，客人就说吃饱了，这是不礼貌的；吃完饭以后，客人一般会向主人说几句感谢的话。",
+      "wordCount": 466,
+      "questions": [
+        {
+          "question": "最适合做本文标题的是：",
+          "type": "multiple_choice",
+          "options": ["A中国人吃饭的规矩", "B中国人怎么请客", "C中国的饮食文化", "D中国人的礼貌"],
+          "correctAnswer": "A中国人吃饭的规矩"
+        },
+        {
+          "question": "\"民以食为天\"的意思是：",
+          "type": "multiple_choice",
+          "options": ["A人们喜欢吃", "B人们觉得吃非常重要", "C人们每天要吃饭", "D为了吃，人们要每天工作"],
+          "correctAnswer": "B人们觉得吃非常重要"
+        }
+      ]
+    }
+  ],
+  "exercises": [
+    {
+      "type": "character_inference",
+      "title": "运用汉字知识推断字义 (Infer meaning from character components)",
+      "description": "Use radical knowledge to infer the meaning of unfamiliar characters",
+      "questions": [
+        {
+          "question": "菜刚做好，太烫了。",
+          "options": ["A非常饿", "B非常热", "C非常好吃"],
+          "correctAnswer": "B非常热",
+          "hint": "烫 has the fire radical 火"
+        },
+        {
+          "question": "这种苹果比较酸，再看看别的吧。",
+          "options": ["A一种味道", "B一种颜色", "C一种吃的东西"],
+          "correctAnswer": "A一种味道"
+        },
+        {
+          "question": "这个电视节目介绍了糍粑的做法。",
+          "options": ["A一种衣物", "B一种用的东西", "C一种吃的东西"],
+          "correctAnswer": "C一种吃的东西",
+          "hint": "糍粑 has the rice radical 米"
+        }
+      ]
+    }
+  ]
+}
diff --git a/content/chapters/ledu-chapter2.json b/content/chapters/ledu-chapter2.json
new file mode 100644
index 0000000..4ebdbff
--- /dev/null
+++ b/content/chapters/ledu-chapter2.json
@@ -0,0 +1,750 @@
+{
+  "id": "ledu-chapter2",
+  "book_id": "ledu",
+  "name": "货比三家 (Compare Prices at Three Shops)",
+  "description": "Chapter on online shopping, consumer behavior, and China's Double 11 shopping festival. Explores shopping methods, consumer preferences, and the advantages and disadvantages of online shopping.",
+  "difficulty": "intermediate",
+  "language": "zh-CN",
+  "chapter_number": "2",
+  "metadata": {
+    "version": "1.0",
+    "created": "2025-10-14",
+    "updated": "2025-10-14",
+    "source": "LEDU Textbook - Jiaotong University",
+    "target_level": "intermediate",
+    "estimated_hours": 10,
+    "prerequisites": ["ledu-chapter1"],
+    "learning_objectives": [
+      "Master 40+ shopping and consumer vocabulary terms",
+      "Understand Chinese online shopping culture and Double 11",
+      "Learn about consumer behavior and shopping preferences",
+      "Practice reading comprehension with authentic texts",
+      "Develop vocabulary inference skills using affixes"
+    ],
+    "content_tags": ["shopping", "consumer-culture", "online-shopping", "double-11", "chinese-culture"],
+    "completion_criteria": {
+      "vocabulary_mastery": 90,
+      "comprehension_score": 80,
+      "exercises_completed": 20
+    }
+  },
+  "vocabulary": {
+    "品": {
+      "pronunciation": "pǐn",
+      "type": "morpheme",
+      "user_language": "item, product, grade, quality",
+      "examples": ["商品", "产品", "上品", "品茶"],
+      "notes": "Associative character composed of three 口 (mouth). Generally used as morpheme, not alone."
+    },
+    "物": {
+      "pronunciation": "wù",
+      "type": "morpheme",
+      "user_language": "thing, object, matter",
+      "examples": ["动物", "物品", "礼物", "博物馆"],
+      "notes": "Usually used as morpheme, not alone"
+    },
+    "消费": {
+      "pronunciation": "xiāofèi",
+      "type": "verb",
+      "user_language": "to consume",
+      "examples": ["消费水平", "消费者"]
+    },
+    "方式": {
+      "pronunciation": "fāngshì",
+      "type": "noun",
+      "user_language": "way, method, manner",
+      "examples": ["生活方式", "消费方式"]
+    },
+    "打折": {
+      "pronunciation": "dǎ//zhé",
+      "type": "verb",
+      "user_language": "to sell at a discount",
+      "examples": ["打八折", "打折促销"],
+      "notes": "打八折 means 20% off (pay 80%)"
+    },
+    "促销": {
+      "pronunciation": "cùxiāo",
+      "type": "verb",
+      "user_language": "to promote sales",
+      "examples": ["打折促销", "促销员"]
+    },
+    "优惠": {
+      "pronunciation": "yōuhuì",
+      "type": "adjective",
+      "user_language": "preferential, discount",
+      "examples": ["优惠价格", "八折优惠"]
+    },
+    "调查": {
+      "pronunciation": "diàochá",
+      "type": "noun/verb",
+      "user_language": "investigation; to investigate",
+      "examples": ["一项调查", "做调查"]
+    },
+    "需要": {
+      "pronunciation": "xūyào",
+      "type": "verb/noun",
+      "user_language": "to need; need",
+      "examples": ["需要时间", "需要帮助", "工作的需要"]
+    },
+    "实用": {
+      "pronunciation": "shíyòng",
+      "type": "adjective",
+      "user_language": "practical, functional"
+    },
+    "折扣": {
+      "pronunciation": "zhékòu",
+      "type": "noun",
+      "user_language": "discount",
+      "examples": ["有折扣", "折扣价"]
+    },
+    "吸引": {
+      "pronunciation": "xīyǐn",
+      "type": "verb",
+      "user_language": "to attract",
+      "examples": ["吸引人", "有吸引力", "吸引住"]
+    },
+    "产品": {
+      "pronunciation": "chǎnpǐn",
+      "type": "noun",
+      "user_language": "product",
+      "examples": ["进口产品", "产品质量"]
+    },
+    "省": {
+      "pronunciation": "shěng",
+      "type": "verb",
+      "user_language": "to save, to economize",
+      "examples": ["省钱", "省时间", "省心"]
+    },
+    "满意": {
+      "pronunciation": "mǎnyì",
+      "type": "verb",
+      "user_language": "to be satisfied",
+      "examples": ["对…满意"]
+    },
+    "光棍儿节": {
+      "pronunciation": "Guānggùnr Jié",
+      "type": "proper noun",
+      "user_language": "Singles' Day",
+      "notes": "November 11th, because of the four 1's representing single people"
+    },
+    "降": {
+      "pronunciation": "jiàng",
+      "type": "verb",
+      "user_language": "to lower, to reduce"
+    },
+    "涨": {
+      "pronunciation": "zhǎng",
+      "type": "verb",
+      "user_language": "to rise (of prices, water, wages)"
+    },
+    "骗": {
+      "pronunciation": "piàn",
+      "type": "verb",
+      "user_language": "to cheat, to deceive"
+    },
+    "经验": {
+      "pronunciation": "jīngyàn",
+      "type": "noun",
+      "user_language": "experience"
+    },
+    "赚": {
+      "pronunciation": "zhuàn",
+      "type": "verb",
+      "user_language": "to make a profit, to earn"
+    },
+    "服装": {
+      "pronunciation": "fúzhuāng",
+      "type": "noun",
+      "user_language": "clothing, costume"
+    },
+    "满": {
+      "pronunciation": "mǎn",
+      "type": "verb",
+      "user_language": "to reach, to come up to (formal/business)",
+      "examples": ["每满299元"]
+    },
+    "返": {
+      "pronunciation": "fǎn",
+      "type": "verb",
+      "user_language": "to return, to pay back (formal/business)"
+    },
+    "优惠券": {
+      "pronunciation": "yōuhuìquàn",
+      "type": "noun",
+      "user_language": "coupon"
+    },
+    "化妆品": {
+      "pronunciation": "huàzhuāngpǐn",
+      "type": "noun",
+      "user_language": "cosmetics, makeup"
+    },
+    "电饭锅": {
+      "pronunciation": "diànfànguō",
+      "type": "noun",
+      "user_language": "electric rice cooker"
+    },
+    "网购": {
+      "pronunciation": "wǎnggòu",
+      "type": "verb",
+      "user_language": "to shop online"
+    },
+    "近年来": {
+      "pronunciation": "jìn nián lái",
+      "type": "phrase",
+      "user_language": "in recent years"
+    },
+    "已经": {
+      "pronunciation": "yǐjīng",
+      "type": "adverb",
+      "user_language": "already"
+    },
+    "成为": {
+      "pronunciation": "chéngwéi",
+      "type": "verb",
+      "user_language": "to become"
+    },
+    "日常": {
+      "pronunciation": "rìcháng",
+      "type": "adjective",
+      "user_language": "daily, everyday"
+    },
+    "谈到": {
+      "pronunciation": "tándào",
+      "type": "verb",
+      "user_language": "to mention, to talk about"
+    },
+    "首先": {
+      "pronunciation": "shǒuxiān",
+      "type": "adverb",
+      "user_language": "first, firstly"
+    },
+    "想到": {
+      "pronunciation": "xiǎngdào",
+      "type": "verb",
+      "user_language": "to think of"
+    },
+    "双十一": {
+      "pronunciation": "shuāng shí yī",
+      "type": "proper noun",
+      "user_language": "Double 11 (November 11)"
+    },
+    "单身": {
+      "pronunciation": "dānshēn",
+      "type": "adjective",
+      "user_language": "single (unmarried)"
+    },
+    "后来": {
+      "pronunciation": "hòulái",
+      "type": "adverb",
+      "user_language": "later, afterwards"
+    },
+    "说法": {
+      "pronunciation": "shuōfǎ",
+      "type": "noun",
+      "user_language": "way of saying, statement"
+    },
+    "计划": {
+      "pronunciation": "jìhuà",
+      "type": "verb/noun",
+      "user_language": "to plan; plan"
+    },
+    "举办": {
+      "pronunciation": "jǔbàn",
+      "type": "verb",
+      "user_language": "to hold, to organize (event)"
+    },
+    "购物节": {
+      "pronunciation": "gòuwù jié",
+      "type": "noun",
+      "user_language": "shopping festival"
+    },
+    "选择": {
+      "pronunciation": "xuǎnzé",
+      "type": "verb",
+      "user_language": "to choose, to select"
+    },
+    "刚好": {
+      "pronunciation": "gānghǎo",
+      "type": "adverb",
+      "user_language": "just right, exactly"
+    },
+    "购买": {
+      "pronunciation": "gòumǎi",
+      "type": "verb",
+      "user_language": "to purchase"
+    },
+    "网友": {
+      "pronunciation": "wǎngyǒu",
+      "type": "noun",
+      "user_language": "netizen, internet user"
+    },
+    "戏称": {
+      "pronunciation": "xìchēng",
+      "type": "verb",
+      "user_language": "to jokingly call"
+    },
+    "每年": {
+      "pronunciation": "měinián",
+      "type": "noun",
+      "user_language": "every year"
+    },
+    "电商网站": {
+      "pronunciation": "diànshāng wǎngzhàn",
+      "type": "noun",
+      "user_language": "e-commerce website"
+    },
+    "价格": {
+      "pronunciation": "jiàgé",
+      "type": "noun",
+      "user_language": "price"
+    },
+    "一般": {
+      "pronunciation": "yībān",
+      "type": "adverb",
+      "user_language": "generally, usually"
+    },
+    "平时": {
+      "pronunciation": "píngshí",
+      "type": "noun",
+      "user_language": "usually, ordinarily"
+    },
+    "物美价廉": {
+      "pronunciation": "wù měi jià lián",
+      "type": "idiom",
+      "user_language": "good quality and cheap price"
+    },
+    "网站": {
+      "pronunciation": "wǎngzhàn",
+      "type": "noun",
+      "user_language": "website"
+    },
+    "其中": {
+      "pronunciation": "qízhōng",
+      "type": "pronoun",
+      "user_language": "among them"
+    },
+    "大部分": {
+      "pronunciation": "dà bùfen",
+      "type": "noun",
+      "user_language": "most, the majority"
+    },
+    "认为": {
+      "pronunciation": "rènwéi",
+      "type": "verb",
+      "user_language": "to think, to believe"
+    },
+    "买到": {
+      "pronunciation": "mǎidào",
+      "type": "verb",
+      "user_language": "to buy (successfully)"
+    },
+    "便宜": {
+      "pronunciation": "piányi",
+      "type": "adjective",
+      "user_language": "cheap, inexpensive"
+    },
+    "而且": {
+      "pronunciation": "érqiě",
+      "type": "conjunction",
+      "user_language": "and, moreover"
+    },
+    "现在": {
+      "pronunciation": "xiànzài",
+      "type": "noun",
+      "user_language": "now, currently"
+    },
+    "东西": {
+      "pronunciation": "dōngxi",
+      "type": "noun",
+      "user_language": "thing, stuff"
+    },
+    "参加": {
+      "pronunciation": "cānjiā",
+      "type": "verb",
+      "user_language": "to participate"
+    },
+    "觉得": {
+      "pronunciation": "juéde",
+      "type": "verb",
+      "user_language": "to feel, to think"
+    },
+    "特别": {
+      "pronunciation": "tèbié",
+      "type": "adverb",
+      "user_language": "especially, particularly"
+    },
+    "工作": {
+      "pronunciation": "gōngzuò",
+      "type": "noun/verb",
+      "user_language": "work, job; to work"
+    },
+    "忙": {
+      "pronunciation": "máng",
+      "type": "adjective",
+      "user_language": "busy"
+    },
+    "时间": {
+      "pronunciation": "shíjiān",
+      "type": "noun",
+      "user_language": "time"
+    },
+    "感觉": {
+      "pronunciation": "gǎnjué",
+      "type": "verb",
+      "user_language": "to feel"
+    },
+    "男性": {
+      "pronunciation": "nánxìng",
+      "type": "noun",
+      "user_language": "male"
+    },
+    "女性": {
+      "pronunciation": "nǚxìng",
+      "type": "noun",
+      "user_language": "female"
+    },
+    "吸引力": {
+      "pronunciation": "xīyǐnlì",
+      "type": "noun",
+      "user_language": "attraction, appeal"
+    },
+    "日用百货": {
+      "pronunciation": "rìyòng bǎihuò",
+      "type": "noun",
+      "user_language": "daily necessities"
+    },
+    "家电": {
+      "pronunciation": "jiādiàn",
+      "type": "noun",
+      "user_language": "household appliances"
+    },
+    "数码产品": {
+      "pronunciation": "shùmǎ chǎnpǐn",
+      "type": "noun",
+      "user_language": "digital products"
+    },
+    "有利有弊": {
+      "pronunciation": "yǒu lì yǒu bì",
+      "type": "idiom",
+      "user_language": "has advantages and disadvantages"
+    },
+    "方便": {
+      "pronunciation": "fāngbiàn",
+      "type": "adjective",
+      "user_language": "convenient"
+    },
+    "购物": {
+      "pronunciation": "gòuwù",
+      "type": "verb",
+      "user_language": "shopping"
+    },
+    "乐趣": {
+      "pronunciation": "lèqù",
+      "type": "noun",
+      "user_language": "pleasure, joy"
+    },
+    "但是": {
+      "pronunciation": "dànshì",
+      "type": "conjunction",
+      "user_language": "but, however"
+    },
+    "有时": {
+      "pronunciation": "yǒushí",
+      "type": "adverb",
+      "user_language": "sometimes"
+    },
+    "商品": {
+      "pronunciation": "shāngpǐn",
+      "type": "noun",
+      "user_language": "goods, merchandise"
+    },
+    "本来": {
+      "pronunciation": "běnlái",
+      "type": "adverb",
+      "user_language": "originally"
+    },
+    "为了": {
+      "pronunciation": "wèile",
+      "type": "preposition",
+      "user_language": "in order to, for"
+    },
+    "却": {
+      "pronunciation": "què",
+      "type": "adverb",
+      "user_language": "however, but"
+    },
+    "钱": {
+      "pronunciation": "qián",
+      "type": "noun",
+      "user_language": "money"
+    },
+    "真正": {
+      "pronunciation": "zhēnzhēng",
+      "type": "adjective",
+      "user_language": "real, genuine"
+    },
+    "降价": {
+      "pronunciation": "jiàngjià",
+      "type": "verb",
+      "user_language": "to reduce prices"
+    },
+    "涨价": {
+      "pronunciation": "zhǎngjià",
+      "type": "verb",
+      "user_language": "to increase prices"
+    },
+    "新手": {
+      "pronunciation": "xīnshǒu",
+      "type": "noun",
+      "user_language": "novice, beginner"
+    },
+    "不用": {
+      "pronunciation": "bùyòng",
+      "type": "auxiliary verb",
+      "user_language": "no need to"
+    },
+    "价廉物美": {
+      "pronunciation": "jià lián wù měi",
+      "type": "idiom",
+      "user_language": "cheap and good quality"
+    },
+    "为什么": {
+      "pronunciation": "wèishénme",
+      "type": "pronoun",
+      "user_language": "why"
+    },
+    "会": {
+      "pronunciation": "huì",
+      "type": "auxiliary verb",
+      "user_language": "will"
+    },
+    "可能": {
+      "pronunciation": "kěnéng",
+      "type": "auxiliary verb",
+      "user_language": "possibly, maybe"
+    },
+    "开网店": {
+      "pronunciation": "kāi wǎngdiàn",
+      "type": "verb phrase",
+      "user_language": "to run an online store"
+    },
+    "网店": {
+      "pronunciation": "wǎngdiàn",
+      "type": "noun",
+      "user_language": "online store"
+    },
+    "做生意": {
+      "pronunciation": "zuò shēngyi",
+      "type": "verb phrase",
+      "user_language": "to do business"
+    },
+    "先": {
+      "pronunciation": "xiān",
+      "type": "adverb",
+      "user_language": "first"
+    },
+    "如果": {
+      "pronunciation": "rúguǒ",
+      "type": "conjunction",
+      "user_language": "if"
+    },
+    "对...来说": {
+      "pronunciation": "duì...lái shuō",
+      "type": "phrase",
+      "user_language": "for, as far as...is concerned"
+    },
+    "店主": {
+      "pronunciation": "diànzhǔ",
+      "type": "noun",
+      "user_language": "shop owner"
+    },
+    "期间": {
+      "pronunciation": "qījiān",
+      "type": "noun",
+      "user_language": "period, during"
+    },
+    "主要": {
+      "pronunciation": "zhǔyào",
+      "type": "adverb",
+      "user_language": "mainly"
+    },
+    "人气": {
+      "pronunciation": "rénqì",
+      "type": "noun",
+      "user_language": "popularity"
+    }
+  },
+  "grammar": {
+    "既然": {
+      "title": "既然…… - since, now that",
+      "pattern": "既然 + Reason, Result",
+      "explanation": "Used to express that since a certain condition exists, a certain result follows logically.",
+      "examples": [
+        {
+          "chinese": "既然你这周没有时间，那就下周再去吧。",
+          "pronunciation": "Jìrán nǐ zhè zhōu méiyǒu shíjiān, nà jiù xià zhōu zài qù ba.",
+          "translation": "Since you don't have time this week, let's go next week then."
+        },
+        {
+          "chinese": "既然父母不同意你去国外工作，你就别去了。",
+          "pronunciation": "Jìrán fùmǔ bù tóngyì nǐ qù guówài gōngzuò, nǐ jiù bié qù le.",
+          "translation": "Since your parents don't agree with you working abroad, then don't go."
+        },
+        {
+          "chinese": "既然是自己需要的东西，价格又便宜，为什么不买？",
+          "pronunciation": "Jìrán shì zìjǐ xūyào de dōngxi, jiàgé yòu piányi, wèishénme bù mǎi?",
+          "translation": "Since it's something you need and the price is cheap, why not buy it?"
+        }
+      ]
+    },
+    "自-从-起": {
+      "title": "自/从……起 - from...onwards (written language)",
+      "explanation": "Written Chinese expression meaning '从……开始' (from...starting). More formal.",
+      "examples": [
+        {
+          "chinese": "自今日起至1月1日，本店部分商品半价。",
+          "pronunciation": "Zì jīnrì qǐ zhì 1 yuè 1 rì, běn diàn bùfen shāngpǐn bàn jià.",
+          "translation": "From today until January 1st, some products in this shop are half price."
+        },
+        {
+          "chinese": "从下周起，学校放假。",
+          "pronunciation": "Cóng xià zhōu qǐ, xuéxiào fàngjià.",
+          "translation": "Starting from next week, school is on vacation."
+        }
+      ]
+    },
+    "为-written": {
+      "title": "为 (wèi) - to be (written language)",
+      "explanation": "Written Chinese verb meaning '是' (to be). More formal.",
+      "examples": [
+        {
+          "chinese": "考试时间为两小时。",
+          "pronunciation": "Kǎoshì shíjiān wèi liǎng xiǎoshí.",
+          "translation": "The exam time is two hours."
+        },
+        {
+          "chinese": "公司上班时间为上午9:00至下午5:00。",
+          "pronunciation": "Gōngsī shàngbān shíjiān wèi shàngwǔ 9:00 zhì xiàwǔ 5:00.",
+          "translation": "Company working hours are from 9:00 AM to 5:00 PM."
+        }
+      ]
+    }
+  },
+  "texts": [
+    {
+      "id": "main-text",
+      "title": "\"双十一\"，买还是不买？ (Double 11: To Buy or Not to Buy?)",
+      "type": "main",
+      "content": "近年来，网购已经成为人们的日常消费方式之一。谈到网购，人们首先会想到\"双十一\"。\"双十一\"是什么？这得从\"光棍儿节\"说起。11月11日，因为有4个\"1\"，让人们想到了单身的人——\"光棍儿\"，后来就有了\"光棍儿节\"的说法。2009年，一个网上商城计划举办一个网上购物节，他们选择在11月进行，因为那时刚好是人们购买冬装的时候。11月11日被网友戏称为\"光棍儿节\"，购物节就选在了这一天，\"双十一\"购物节就是这么来的。后来，每年的11月11日0点起，各大电商网站都会打折促销，价格一般都比平时优惠很多。\n\n在物美价廉面前，买还是不买？一家网站做了一个\"双十一\"网购的调查。有75%的网友说会在\"双十一\"网购，其中大部分人认为\"能买到便宜而且现在需要的东西\"；不准备参加的人中，有人觉得\"没有特别想买的东西\"，有人\"工作忙，没有时间\"，还有人\"感觉买的东西不实用\"。男性的热情不比女性低，网购的低折扣对他们也有很大的吸引力。\n\n从调查中可以知道，人们对网购服装、日用百货、家电及数码产品最感兴趣。\n\n网购有利有弊。网购方便、省钱，\"双十一\"给很多人带来了跟平时不一样的购物乐趣。但是，有时人们对买到的商品不太满意，还有人买了很多不需要的东西，本来是为了省钱去网购，却多花了钱。",
+      "wordCount": 536,
+      "questions": [
+        {
+          "question": "文章第1段主要介绍了\"双十一\"的：",
+          "type": "multiple_choice",
+          "options": ["A传统", "B由来", "C促销活动", "D商家"],
+          "correctAnswer": "B由来"
+        },
+        {
+          "question": "人们喜欢在\"双十一\"网购的主要原因是什么？",
+          "type": "multiple_choice",
+          "options": ["A网购比去实体店购物更方便", "B能买到便宜而且需要的东西", "C平时很忙，没有时间买东西", "D网购能给人们带来很多乐趣"],
+          "correctAnswer": "B能买到便宜而且需要的东西"
+        },
+        {
+          "question": "人们不想参加\"双十一\"网购的原因中，下列哪一项文中没有提到？",
+          "type": "multiple_choice",
+          "options": ["A没有想买的东西", "B太忙，没有时间", "C觉得网上的商品质量不好", "D网购的东西可能不太实用"],
+          "correctAnswer": "C觉得网上的商品质量不好"
+        }
+      ]
+    },
+    {
+      "id": "netizen-comments",
+      "title": "关于\"双十一\"的网友评价 (Netizen Comments About Double 11)",
+      "type": "extensive",
+      "content": "网友1：不是真正的降价，不少东西是涨价了，骗骗新手的。\n\n网友2：平时也促销，有折扣，\"双十一\"没有优惠很多，不用急着那一天买。\n\n网友3：省钱最重要，大家都想买到价廉物美的东西。\n\n网友4：既然是自己需要的东西，价格又便宜，为什么不买？\n\n网友5：很多人会买，便宜嘛。不过等不了多久，再看看买回来的东西，大多是用不上的。\n\n网友6：我开网店五年了，\"双十一\"大部分网店会降价，可能极少数网店涨了价，我觉得那些人不是真正做生意的。\n\n网友7：我的经验是\"双十一\"前先在网店看看想买的东西，如果\"双十一\"降价了就买。\n\n网友8：对我们中小店主来说，\"双十一\"期间，钱真赚不了多少，主要是赚人气。",
+      "wordCount": 271,
+      "questions": [
+        {
+          "question": "给\"双十一\"好评的是哪几位网友？",
+          "type": "open",
+          "answer": "网友3、网友4"
+        },
+        {
+          "question": "给\"双十一\"差评的是哪几位网友？",
+          "type": "open",
+          "answer": "网友1、网友2、网友5"
+        },
+        {
+          "question": "哪些网友对\"双十一\"购物给出了建议？",
+          "type": "open",
+          "answer": "网友7：先看价格，如果降价了再买"
+        },
+        {
+          "question": "网友中哪几位是卖家？他们对\"双十一\"是什么态度？",
+          "type": "open",
+          "answer": "网友6、网友8。网友6说大部分网店会降价；网友8说赚不了多少钱，主要是赚人气"
+        }
+      ]
+    }
+  ],
+  "exercises": [
+    {
+      "type": "vocabulary_inference",
+      "title": "通过词缀猜测词义 (Infer meaning through affixes)",
+      "description": "Chinese has morphemes that function like affixes: 家 (expert), 者 (person), 手 (skilled person), 热 (craze)",
+      "questions": [
+        {
+          "question": "这家网站有很多国外的买家。",
+          "hint": "家 = person who does something",
+          "answer": "buyer"
+        },
+        {
+          "question": "这家书店举办了作者与读者见面会。",
+          "hint": "者 = person who does something",
+          "answer": "author and reader"
+        },
+        {
+          "question": "在网上买东西，特别是新手，可能会遇到一些问题。",
+          "hint": "手 = person skilled at something",
+          "answer": "novice, beginner"
+        },
+        {
+          "question": "网购热已经从城市到了乡村。",
+          "hint": "热 = social trend/craze",
+          "answer": "online shopping craze"
+        }
+      ]
+    },
+    {
+      "type": "phrase_matching",
+      "title": "从课文中找出与下列说法意思相近的词语",
+      "questions": [
+        {
+          "question": "东西比以前贵了（网友1）",
+          "answer": "涨价"
+        },
+        {
+          "question": "没有经验的买家（网友1）",
+          "answer": "新手"
+        },
+        {
+          "question": "用打折、送礼物的方式卖东西（网友2）",
+          "answer": "促销"
+        },
+        {
+          "question": "东西好，而且价格便宜（网友3）",
+          "answer": "价廉物美"
+        },
+        {
+          "question": "东西比以前便宜了（网友6）",
+          "answer": "降价"
+        },
+        {
+          "question": "增加受关注、受欢迎的程度（网友8）",
+          "answer": "赚人气"
+        }
+      ]
+    }
+  ]
+}
diff --git a/content/chapters/ledu-chapter3.json b/content/chapters/ledu-chapter3.json
new file mode 100644
index 0000000..5435276
--- /dev/null
+++ b/content/chapters/ledu-chapter3.json
@@ -0,0 +1,643 @@
+{
+  "id": "ledu-chapter3",
+  "book_id": "ledu",
+  "name": "生命在于运动 (Life Lies in Movement)",
+  "description": "Comprehensive chapter on sports, fitness, healthy lifestyle, and the importance of making exercise a habit. Includes reading about ping-pong history and Chinese sports culture.",
+  "difficulty": "intermediate",
+  "language": "zh-CN",
+  "chapter_number": "3",
+  "metadata": {
+    "version": "1.0",
+    "created": "2025-10-14",
+    "updated": "2025-10-14",
+    "source": "LEDU Textbook - Jiaotong University",
+    "target_level": "intermediate",
+    "estimated_hours": 10,
+    "prerequisites": ["ledu-chapter1", "ledu-chapter2"],
+    "learning_objectives": [
+      "Master 35+ sports and fitness vocabulary terms",
+      "Understand strategies for building exercise habits",
+      "Learn about ping-pong history and sports in China",
+      "Practice reading comprehension with authentic texts",
+      "Develop contextual vocabulary inference skills"
+    ],
+    "content_tags": ["sports", "fitness", "health", "habits", "chinese-culture", "ping-pong"],
+    "completion_criteria": {
+      "vocabulary_mastery": 90,
+      "comprehension_score": 80,
+      "exercises_completed": 18
+    }
+  },
+  "vocabulary": {
+    "习惯": {
+      "pronunciation": "xíguàn",
+      "type": "noun",
+      "user_language": "habit",
+      "examples": ["成为习惯", "生活习惯", "好习惯"],
+      "notes": "Can also be used as verb meaning 'to be accustomed to'"
+    },
+    "健身": {
+      "pronunciation": "jiànshēn",
+      "type": "verb",
+      "user_language": "to work out, to do fitness",
+      "examples": ["健身房", "健身运动"],
+      "notes": "Very common word for working out or exercising"
+    },
+    "压力": {
+      "pronunciation": "yālì",
+      "type": "noun",
+      "user_language": "pressure, stress",
+      "examples": ["生活压力", "工作压力", "压力大"]
+    },
+    "锻炼": {
+      "pronunciation": "duànliàn",
+      "type": "verb",
+      "user_language": "to exercise, to work out",
+      "examples": ["锻炼身体", "锻炼能力"]
+    },
+    "身材": {
+      "pronunciation": "shēncái",
+      "type": "noun",
+      "user_language": "figure, physique",
+      "examples": ["身材苗条", "中等身材"]
+    },
+    "放松": {
+      "pronunciation": "fàngsōng",
+      "type": "verb",
+      "user_language": "to relax, to loosen up",
+      "examples": ["放松肌肉", "放松心情", "放松身心"]
+    },
+    "坚持": {
+      "pronunciation": "jiānchí",
+      "type": "verb",
+      "user_language": "to persist, to persevere",
+      "examples": ["坚持运动", "坚持自己的意见", "坚持下来"]
+    },
+    "适应": {
+      "pronunciation": "shìyìng",
+      "type": "verb",
+      "user_language": "to adapt, to adjust to",
+      "examples": ["适应生活", "适应环境"]
+    },
+    "强度": {
+      "pronunciation": "qiángdù",
+      "type": "noun",
+      "user_language": "intensity",
+      "examples": ["运动强度", "工作强度"]
+    },
+    "体": {
+      "pronunciation": "tǐ",
+      "type": "noun/morpheme",
+      "user_language": "body",
+      "examples": ["体重", "体育", "物体", "体验"],
+      "notes": "Usually used as morpheme, not alone"
+    },
+    "力": {
+      "pronunciation": "lì",
+      "type": "noun/morpheme",
+      "user_language": "force, power",
+      "examples": ["体力", "风力", "听力", "视力"],
+      "notes": "Usually used as morpheme"
+    },
+    "伦敦": {
+      "pronunciation": "Lúndūn",
+      "type": "proper noun",
+      "user_language": "London"
+    },
+    "绳子": {
+      "pronunciation": "shéngzi",
+      "type": "noun",
+      "user_language": "rope"
+    },
+    "软木塞": {
+      "pronunciation": "ruǎnmùsāi",
+      "type": "noun",
+      "user_language": "cork"
+    },
+    "欧洲": {
+      "pronunciation": "Ōuzhōu",
+      "type": "proper noun",
+      "user_language": "Europe"
+    },
+    "流行": {
+      "pronunciation": "liúxíng",
+      "type": "verb",
+      "user_language": "to be popular, to prevail"
+    },
+    "世乒赛": {
+      "pronunciation": "Shìpīngsài",
+      "type": "proper noun",
+      "user_language": "World Table Tennis Championships"
+    },
+    "举办": {
+      "pronunciation": "jǔbàn",
+      "type": "verb",
+      "user_language": "to hold, to organize (an event)"
+    },
+    "娱乐": {
+      "pronunciation": "yúlè",
+      "type": "verb/noun",
+      "user_language": "to entertain; entertainment"
+    },
+    "东亚": {
+      "pronunciation": "Dōng Yà",
+      "type": "proper noun",
+      "user_language": "East Asia"
+    },
+    "接触": {
+      "pronunciation": "jiēchù",
+      "type": "verb",
+      "user_language": "to touch, to have contact with"
+    },
+    "技巧": {
+      "pronunciation": "jìqiǎo",
+      "type": "noun",
+      "user_language": "technique, skill"
+    },
+    "胜": {
+      "pronunciation": "shèng",
+      "type": "verb",
+      "user_language": "to win, to triumph"
+    },
+    "冠军": {
+      "pronunciation": "guànjūn",
+      "type": "noun",
+      "user_language": "champion"
+    },
+    "迎战": {
+      "pronunciation": "yíngzhàn",
+      "type": "verb",
+      "user_language": "to face (in a match)"
+    },
+    "击败": {
+      "pronunciation": "jībài",
+      "type": "verb",
+      "user_language": "to defeat, to beat"
+    },
+    "以弱胜强": {
+      "pronunciation": "yǐ ruò shèng qiáng",
+      "type": "idiom",
+      "user_language": "to defeat the strong with the weak"
+    },
+    "瑜伽": {
+      "pronunciation": "yújiā",
+      "type": "noun",
+      "user_language": "yoga"
+    },
+    "街舞": {
+      "pronunciation": "jiēwǔ",
+      "type": "noun",
+      "user_language": "street dance"
+    },
+    "肚皮舞": {
+      "pronunciation": "dùpíwǔ",
+      "type": "noun",
+      "user_language": "belly dance"
+    },
+    "拉丁舞": {
+      "pronunciation": "lādīngwǔ",
+      "type": "noun",
+      "user_language": "Latin dance"
+    },
+    "芭蕾舞": {
+      "pronunciation": "bālěiwǔ",
+      "type": "noun",
+      "user_language": "ballet"
+    },
+    "有氧操": {
+      "pronunciation": "yǒuyǎngcāo",
+      "type": "noun",
+      "user_language": "aerobics"
+    },
+    "普拉提": {
+      "pronunciation": "pǔlātí",
+      "type": "noun",
+      "user_language": "Pilates"
+    },
+    "便": {
+      "pronunciation": "biàn",
+      "type": "adverb",
+      "user_language": "then, therefore (written language)",
+      "examples": ["他很好学，不懂便问", "他们俩大学一毕业便结婚了"],
+      "notes": "Written Chinese, means '就'"
+    },
+    "以": {
+      "pronunciation": "yǐ",
+      "type": "preposition",
+      "user_language": "with, to use (written language)",
+      "examples": ["孩子不应该以这种态度跟父母说话", "以什么样的方法教孩子"],
+      "notes": "Written Chinese, means '用'"
+    },
+    "着迷": {
+      "pronunciation": "zháomí",
+      "type": "verb",
+      "user_language": "to be fascinated, to be captivated"
+    },
+    "只要": {
+      "pronunciation": "zhǐyào",
+      "type": "conjunction",
+      "user_language": "as long as, so long as"
+    },
+    "改变": {
+      "pronunciation": "gǎibiàn",
+      "type": "verb",
+      "user_language": "to change"
+    },
+    "生活方式": {
+      "pronunciation": "shēnghuó fāngshì",
+      "type": "noun",
+      "user_language": "lifestyle"
+    },
+    "成为": {
+      "pronunciation": "chéngwéi",
+      "type": "verb",
+      "user_language": "to become"
+    },
+    "舒服": {
+      "pronunciation": "shūfu",
+      "type": "adjective",
+      "user_language": "comfortable"
+    },
+    "秘诀": {
+      "pronunciation": "mìjué",
+      "type": "noun",
+      "user_language": "secret, key, tip"
+    },
+    "定": {
+      "pronunciation": "dìng",
+      "type": "verb",
+      "user_language": "to fix, to set"
+    },
+    "运动量": {
+      "pronunciation": "yùndòngliàng",
+      "type": "noun",
+      "user_language": "amount of exercise"
+    },
+    "慢慢地": {
+      "pronunciation": "mànmàn de",
+      "type": "adverb",
+      "user_language": "slowly, gradually"
+    },
+    "加大": {
+      "pronunciation": "jiādà",
+      "type": "verb",
+      "user_language": "to increase, to enlarge"
+    },
+    "尝试": {
+      "pronunciation": "chángshì",
+      "type": "verb",
+      "user_language": "to try, to attempt"
+    },
+    "项目": {
+      "pronunciation": "xiàngmù",
+      "type": "noun",
+      "user_language": "project, item, event"
+    },
+    "部位": {
+      "pronunciation": "bùwèi",
+      "type": "noun",
+      "user_language": "part, location (of body)"
+    },
+    "增加": {
+      "pronunciation": "zēngjiā",
+      "type": "verb",
+      "user_language": "to increase, to add"
+    },
+    "偷懒": {
+      "pronunciation": "tōulǎn",
+      "type": "verb",
+      "user_language": "to be lazy, to slack off"
+    },
+    "装备": {
+      "pronunciation": "zhuāngbèi",
+      "type": "noun",
+      "user_language": "equipment, gear"
+    },
+    "穿戴": {
+      "pronunciation": "chuāndài",
+      "type": "verb",
+      "user_language": "to wear, to put on"
+    },
+    "准备": {
+      "pronunciation": "zhǔnbèi",
+      "type": "verb",
+      "user_language": "to prepare, to get ready"
+    },
+    "变成": {
+      "pronunciation": "biànchéng",
+      "type": "verb",
+      "user_language": "to become, to turn into"
+    },
+    "当然": {
+      "pronunciation": "dāngrán",
+      "type": "adverb",
+      "user_language": "of course, naturally"
+    },
+    "愿意": {
+      "pronunciation": "yuànyì",
+      "type": "auxiliary verb",
+      "user_language": "willing, to be willing"
+    },
+    "重要": {
+      "pronunciation": "zhòngyào",
+      "type": "adjective",
+      "user_language": "important"
+    },
+    "据说": {
+      "pronunciation": "jùshuō",
+      "type": "verb",
+      "user_language": "it is said, allegedly"
+    },
+    "世纪": {
+      "pronunciation": "shìjì",
+      "type": "noun",
+      "user_language": "century"
+    },
+    "天气": {
+      "pronunciation": "tiānqì",
+      "type": "noun",
+      "user_language": "weather"
+    },
+    "网球": {
+      "pronunciation": "wǎngqiú",
+      "type": "noun",
+      "user_language": "tennis"
+    },
+    "办法": {
+      "pronunciation": "bànfǎ",
+      "type": "noun",
+      "user_language": "method, way, solution"
+    },
+    "餐桌": {
+      "pronunciation": "cānzhuō",
+      "type": "noun",
+      "user_language": "dining table"
+    },
+    "诞生": {
+      "pronunciation": "dànshēng",
+      "type": "verb",
+      "user_language": "to be born, to come into being"
+    },
+    "出现": {
+      "pronunciation": "chūxiàn",
+      "type": "verb",
+      "user_language": "to appear, to emerge"
+    },
+    "不久": {
+      "pronunciation": "bùjiǔ",
+      "type": "noun",
+      "user_language": "soon, before long"
+    },
+    "受欢迎": {
+      "pronunciation": "shòu huānyíng",
+      "type": "verb phrase",
+      "user_language": "to be popular, to be welcomed"
+    },
+    "各国": {
+      "pronunciation": "gèguó",
+      "type": "noun",
+      "user_language": "various countries"
+    },
+    "起源地": {
+      "pronunciation": "qǐyuándì",
+      "type": "noun",
+      "user_language": "place of origin"
+    },
+    "成绩": {
+      "pronunciation": "chéngjī",
+      "type": "noun",
+      "user_language": "result, achievement, grade"
+    },
+    "当作": {
+      "pronunciation": "dàngzuò",
+      "type": "verb",
+      "user_language": "to regard as, to treat as"
+    },
+    "活动": {
+      "pronunciation": "huódòng",
+      "type": "noun",
+      "user_language": "activity"
+    },
+    "来到": {
+      "pronunciation": "láidào",
+      "type": "verb",
+      "user_language": "to arrive, to come to"
+    },
+    "场地": {
+      "pronunciation": "chǎngdì",
+      "type": "noun",
+      "user_language": "venue, space, field"
+    },
+    "用具": {
+      "pronunciation": "yòngjù",
+      "type": "noun",
+      "user_language": "equipment, utensil"
+    },
+    "简单": {
+      "pronunciation": "jiǎndān",
+      "type": "adjective",
+      "user_language": "simple, easy"
+    },
+    "另外": {
+      "pronunciation": "lìngwài",
+      "type": "conjunction",
+      "user_language": "in addition, besides"
+    },
+    "喜欢": {
+      "pronunciation": "xǐhuan",
+      "type": "verb",
+      "user_language": "to like"
+    },
+    "身体": {
+      "pronunciation": "shēntǐ",
+      "type": "noun",
+      "user_language": "body"
+    },
+    "取胜": {
+      "pronunciation": "qǔshèng",
+      "type": "verb",
+      "user_language": "to win, to triumph"
+    },
+    "因此": {
+      "pronunciation": "yīncǐ",
+      "type": "conjunction",
+      "user_language": "therefore, thus"
+    },
+    "发展": {
+      "pronunciation": "fāzhǎn",
+      "type": "verb",
+      "user_language": "to develop"
+    },
+    "多年来": {
+      "pronunciation": "duō nián lái",
+      "type": "phrase",
+      "user_language": "for many years"
+    },
+    "世界": {
+      "pronunciation": "shìjiè",
+      "type": "noun",
+      "user_language": "world"
+    },
+    "比赛": {
+      "pronunciation": "bǐsài",
+      "type": "noun",
+      "user_language": "competition, match"
+    },
+    "选手": {
+      "pronunciation": "xuǎnshǒu",
+      "type": "noun",
+      "user_language": "player, athlete"
+    },
+    "叫": {
+      "pronunciation": "jiào",
+      "type": "verb",
+      "user_language": "to call, to be called"
+    },
+    "从此": {
+      "pronunciation": "cóngcǐ",
+      "type": "adverb",
+      "user_language": "from then on, since then"
+    },
+    "传到": {
+      "pronunciation": "chuándào",
+      "type": "verb",
+      "user_language": "to spread to, to reach"
+    },
+    "目前": {
+      "pronunciation": "mùqián",
+      "type": "noun",
+      "user_language": "currently, at present"
+    },
+    "水平": {
+      "pronunciation": "shuǐpíng",
+      "type": "noun",
+      "user_language": "level, standard"
+    },
+    "国球": {
+      "pronunciation": "guóqiú",
+      "type": "noun",
+      "user_language": "national ball game"
+    }
+  },
+  "grammar": {
+    "既-又-也": {
+      "title": "既……（，）又/也…… - both...and...",
+      "pattern": "既 + Adj/Verb + 又/也 + Adj/Verb",
+      "explanation": "Used to express that something has two qualities or characteristics at the same time",
+      "examples": [
+        {
+          "chinese": "这个孩子既聪明又可爱。",
+          "pronunciation": "Zhège háizi jì cōngming yòu kě'ài.",
+          "translation": "This child is both intelligent and cute."
+        },
+        {
+          "chinese": "他既会踢足球，也会打篮球。",
+          "pronunciation": "Tā jì huì tī zúqiú, yě huì dǎ lánqiú.",
+          "translation": "He can both play soccer and basketball."
+        },
+        {
+          "chinese": "不同的运动既能锻炼身体的不同部位，也可以增加运动的乐趣。",
+          "pronunciation": "Bùtóng de yùndòng jì néng duànliàn shēntǐ de bùtóng bùwèi, yě kěyǐ zēngjiā yùndòng de lèqù.",
+          "translation": "Different sports can both train different parts of the body and increase the enjoyment of exercise."
+        }
+      ]
+    },
+    "便-written": {
+      "title": "便 (biàn) - then, therefore (written language)",
+      "explanation": "Used in written Chinese to mean '就' (then, therefore). More formal than 就.",
+      "examples": [
+        {
+          "chinese": "他很好学，不懂便问。",
+          "pronunciation": "Tā hěn hàoxué, bù dǒng biàn wèn.",
+          "translation": "He is studious; when he doesn't understand, he asks right away."
+        },
+        {
+          "chinese": "他们俩大学一毕业便结婚了。",
+          "pronunciation": "Tāmen liǎ dàxué yī bìyè biàn jiéhūn le.",
+          "translation": "As soon as they graduated from university, they got married."
+        }
+      ]
+    },
+    "以-written": {
+      "title": "以 (yǐ) - with, to use (written language)",
+      "explanation": "Used in written Chinese to mean '用' (to use). More formal writing style.",
+      "examples": [
+        {
+          "chinese": "孩子不应该以这种态度跟父母说话。",
+          "pronunciation": "Háizi bù yīnggāi yǐ zhè zhǒng tàidu gēn fùmǔ shuōhuà.",
+          "translation": "A child should not speak to parents with this kind of attitude."
+        },
+        {
+          "chinese": "父母要好好想一想，以什么样的方法教孩子更好。",
+          "pronunciation": "Fùmǔ yào hǎohao xiǎng yīxiǎng, yǐ shénme yàng de fāngfǎ jiāo háizi gèng hǎo.",
+          "translation": "Parents should think carefully about what method to use to teach their children better."
+        }
+      ]
+    }
+  },
+  "texts": [
+    {
+      "id": "main-text",
+      "title": "让运动成为习惯 (Make Exercise Become a Habit)",
+      "type": "main",
+      "content": "让运动成为习惯？很多人觉得上班都那么忙、那么累了，哪里有时间和力气去运动健身？但有健身经验的人便会明白，压力越大越应该锻炼，因为它不仅可以让你拥有好身材，而且可以放松身心，带给人健康和快乐。\n\n其实，万事开头难，只要改变一下你的生活方式，把开头的那一段日子坚持下来，就能让你对运动着迷。每天的健身就会跟吃饭、睡觉一样，成为你生活中不可缺少的一部分，哪天不运动你就会觉得不舒服。那么，让运动成为习惯有哪些秘诀呢？\n\n第一，定好运动的时间，每天都是这个时间，不要改变。\n\n第二，开始时运动量不要太大，只锻炼10～15分钟就可以了，而且不要做强度太大的运动，要让你的身体慢慢地适应。然后可以慢慢地加大运动量和运动强度，不过最少在两周以后再这样做。\n\n第三，多尝试几种运动项目，不同的运动既能锻炼身体的不同部位，也可以增加运动的乐趣。\n\n第四，和朋友一起去健身，这样如果想要偷懒，会有人看着你。\n\n第五，给自己买些开心的运动装备，穿戴上它们会让自己的身心做好准备。\n\n第六，让运动变成一种快乐，如果运动让你感到快乐，你当然愿意去做。\n\n当然，最重要的一点——贵在坚持。",
+      "wordCount": 488,
+      "questions": [
+        {
+          "question": "课文中提到了哪些让运动成为习惯的方法？",
+          "type": "open",
+          "answer": "六个方法加一个重点：1)定好时间 2)开始时运动量不要太大 3)多尝试几种运动 4)和朋友一起 5)买开心的运动装备 6)让运动变成快乐 重点：贵在坚持"
+        },
+        {
+          "question": "句子中的\"它\"说的是：A压力 B锻炼",
+          "type": "multiple_choice",
+          "options": ["A压力", "B锻炼"],
+          "correctAnswer": "B锻炼"
+        },
+        {
+          "question": "让运动成为习惯最重要的是什么？",
+          "type": "multiple_choice",
+          "options": ["A找到喜欢的运动", "B定好运动的时间", "C多尝试几种运动", "D要每天坚持运动"],
+          "correctAnswer": "D要每天坚持运动"
+        }
+      ]
+    },
+    {
+      "id": "pingpong-text",
+      "title": "乒乓球的由来 (The Origin of Ping-Pong)",
+      "type": "extensive",
+      "content": "乒乓球英文叫作table tennis，它是怎么来的呢？据说，在19世纪末的一天，伦敦天气非常热，而且有雨。有两个年轻人不能去外边打网球，就想了一个办法，以饭馆的大餐桌作球台，中间用绳子作网，酒瓶的软木塞作球，用烟盒打球。女店主见到了，大声说\"Table Tennis！Table Tennis！\"就这样，乒乓球运动诞生了。\n\n乒乓球出现后不久，便成了一种很受欢迎的运动，在欧洲各国流行。1926年，第一届世乒赛在乒乓球的起源地——伦敦举办，但英国人的比赛成绩不太好，他们没有真正重视这项运动，只是把乒乓球当作娱乐活动。\n\n乒乓球运动在20世纪初来到东亚。东亚国家人多地少，乒乓球只需要很小的场地，用具也很简单，室内室外都可以打。另外，东亚人更喜欢没有身体接触的运动，讲究以技巧取胜。因此乒乓球在东亚很受欢迎，快速发展了起来。多年来，世界上各种乒乓球比赛的冠军大多是中、日、韩等东亚国家的选手。\n\n为什么叫\"乒乓球\"呢？20世纪初，一位美国乒乓球用具生产商以打乒乓球时发出的\"ping-pong\"声作为商标名。从此，ping-pong成了乒乓球的另一个英文名。传到中国后，中文里就有了\"乒乓球\"这个新词。中国人喜爱打乒乓球，是目前世界上乒乓球运动水平最高的国家之一，乒乓球也被中国人叫作\"国球\"。",
+      "wordCount": 483,
+      "questions": [
+        {
+          "question": "说说乒乓球运动是怎么来的。",
+          "type": "open",
+          "answer": "19世纪末伦敦，两个年轻人因为下雨不能去外面打网球，用餐桌、绳子、软木塞和烟盒创造了这项运动"
+        },
+        {
+          "question": "乒乓球运动最早起源于英国，为什么却在东亚地区快速发展起来？",
+          "type": "open",
+          "answer": "因为东亚人多地少，乒乓球场地小、用具简单；东亚人喜欢没有身体接触的运动，讲究技巧"
+        }
+      ]
+    }
+  ],
+  "exercises": [
+    {
+      "type": "character_inference",
+      "title": "根据搭配的词语猜测词义",
+      "questions": [
+        {
+          "question": "运动不仅可以强身健体，而且可以带来快乐。",
+          "options": ["A只有", "B不管", "C不但"],
+          "correctAnswer": "C不但"
+        },
+        {
+          "question": "他不想干这么累的活儿。",
+          "options": ["A工作", "B运动", "C学习"],
+          "correctAnswer": "A工作"
+        }
+      ]
+    }
+  ]
+}
diff --git a/content/chapters/ledu-chapter4.json b/content/chapters/ledu-chapter4.json
new file mode 100644
index 0000000..9832a06
--- /dev/null
+++ b/content/chapters/ledu-chapter4.json
@@ -0,0 +1,762 @@
+{
+  "id": "ledu-chapter4",
+  "book_id": "ledu",
+  "name": "绿色生活 (Green Living)",
+  "description": "Chapter on environmental protection, green transportation, and sustainable lifestyle. Explores traffic problems in big cities, World Car Free Day, and daily environmental actions.",
+  "difficulty": "intermediate",
+  "language": "zh-CN",
+  "chapter_number": "4",
+  "metadata": {
+    "version": "1.0",
+    "created": "2025-10-14",
+    "updated": "2025-10-14",
+    "source": "LEDU Textbook - Jiaotong University",
+    "target_level": "intermediate",
+    "estimated_hours": 10,
+    "prerequisites": ["ledu-chapter1", "ledu-chapter2", "ledu-chapter3"],
+    "learning_objectives": [
+      "Master 90+ environmental and transportation vocabulary",
+      "Understand green living concepts and practices",
+      "Learn about traffic management in Chinese cities",
+      "Practice reading comprehension with authentic texts",
+      "Develop abbreviation recognition skills"
+    ],
+    "content_tags": ["environment", "transportation", "green-living", "pollution", "sustainability", "chinese-culture"],
+    "completion_criteria": {
+      "vocabulary_mastery": 90,
+      "comprehension_score": 80,
+      "exercises_completed": 20
+    }
+  },
+  "vocabulary": {
+    "生": {
+      "pronunciation": "shēng",
+      "type": "morpheme",
+      "user_language": "to be born, life, to grow",
+      "examples": ["出生", "生长", "生活", "发生"],
+      "notes": "Self-explanatory character showing grass growing from earth"
+    },
+    "出": {
+      "pronunciation": "chū",
+      "type": "verb/morpheme",
+      "user_language": "to go out, to come out",
+      "examples": ["出门", "出主意", "出问题", "出汗"]
+    },
+    "交通": {
+      "pronunciation": "jiāotōng",
+      "type": "noun",
+      "user_language": "traffic, transportation",
+      "examples": ["交通便利", "交通安全", "交通部门"]
+    },
+    "拥堵": {
+      "pronunciation": "yōngdǔ",
+      "type": "verb",
+      "user_language": "to be stuck in (a traffic jam)",
+      "examples": ["交通拥堵", "道路拥堵"]
+    },
+    "解决": {
+      "pronunciation": "jiějué",
+      "type": "verb",
+      "user_language": "to solve, to settle",
+      "examples": ["解决问题"]
+    },
+    "发展": {
+      "pronunciation": "fāzhǎn",
+      "type": "verb",
+      "user_language": "to develop",
+      "examples": ["发展公共交通", "发展经济", "发展速度"]
+    },
+    "租": {
+      "pronunciation": "zū",
+      "type": "verb/noun",
+      "user_language": "to rent; rent",
+      "examples": ["租房", "租车", "房租", "租金"]
+    },
+    "控制": {
+      "pronunciation": "kòngzhì",
+      "type": "verb",
+      "user_language": "to control, to dominate",
+      "examples": ["控制比赛", "控制数量"]
+    },
+    "鼓励": {
+      "pronunciation": "gǔlì",
+      "type": "verb",
+      "user_language": "to encourage",
+      "examples": ["鼓励学生", "互相鼓励", "得到鼓励"]
+    },
+    "污染": {
+      "pronunciation": "wūrǎn",
+      "type": "verb/noun",
+      "user_language": "to pollute; pollution",
+      "examples": ["污染空气", "污染环境", "受到污染"]
+    },
+    "噪声": {
+      "pronunciation": "zàoshēng",
+      "type": "noun",
+      "user_language": "noise",
+      "examples": ["噪声污染"]
+    },
+    "资源": {
+      "pronunciation": "zīyuán",
+      "type": "noun",
+      "user_language": "resource(s)",
+      "examples": ["自然资源", "人力资源", "资源丰富"]
+    },
+    "提高": {
+      "pronunciation": "tí//gāo",
+      "type": "verb",
+      "user_language": "to improve, to increase, to enhance",
+      "examples": ["提高水平", "提高能力"]
+    },
+    "意识": {
+      "pronunciation": "yìshí",
+      "type": "noun/verb",
+      "user_language": "awareness; to be conscious of, to realize",
+      "examples": ["安全意识", "环境保护意识"]
+    },
+    "世界无车日": {
+      "pronunciation": "Shìjiè Wúchē Rì",
+      "type": "proper noun",
+      "user_language": "World Car Free Day"
+    },
+    "朝阳区": {
+      "pronunciation": "Cháoyáng Qū",
+      "type": "proper noun",
+      "user_language": "Chaoyang District (of Beijing)"
+    },
+    "法国": {
+      "pronunciation": "Fǎguó",
+      "type": "proper noun",
+      "user_language": "France"
+    },
+    "抱怨": {
+      "pronunciation": "bàoyuàn",
+      "type": "verb",
+      "user_language": "to complain"
+    },
+    "糟糕": {
+      "pronunciation": "zāogāo",
+      "type": "adjective",
+      "user_language": "terrible, too bad"
+    },
+    "节约": {
+      "pronunciation": "jiéyuē",
+      "type": "verb",
+      "user_language": "to economize, to save"
+    },
+    "告示": {
+      "pronunciation": "gàoshi",
+      "type": "noun",
+      "user_language": "bulletin, official notice"
+    },
+    "法院": {
+      "pronunciation": "fǎyuàn",
+      "type": "noun",
+      "user_language": "court of justice"
+    },
+    "通病": {
+      "pronunciation": "tōngbìng",
+      "type": "noun",
+      "user_language": "common problem, common defect"
+    },
+    "便利": {
+      "pronunciation": "biànlì",
+      "type": "adjective",
+      "user_language": "convenient, easy"
+    },
+    "出行": {
+      "pronunciation": "chūxíng",
+      "type": "verb",
+      "user_language": "to go out, to travel"
+    },
+    "管理": {
+      "pronunciation": "guǎnlǐ",
+      "type": "verb/noun",
+      "user_language": "to manage; management",
+      "examples": ["交通管理部门"]
+    },
+    "部门": {
+      "pronunciation": "bùmén",
+      "type": "noun",
+      "user_language": "department, section"
+    },
+    "修建": {
+      "pronunciation": "xiūjiàn",
+      "type": "verb",
+      "user_language": "to build, to construct"
+    },
+    "地铁": {
+      "pronunciation": "dìtiě",
+      "type": "noun",
+      "user_language": "subway, metro"
+    },
+    "自行车": {
+      "pronunciation": "zìxíngchē",
+      "type": "noun",
+      "user_language": "bicycle"
+    },
+    "数量": {
+      "pronunciation": "shùliàng",
+      "type": "noun",
+      "user_language": "quantity, amount"
+    },
+    "市民": {
+      "pronunciation": "shìmín",
+      "type": "noun",
+      "user_language": "citizen, city resident"
+    },
+    "步行": {
+      "pronunciation": "bùxíng",
+      "type": "verb",
+      "user_language": "to walk, on foot"
+    },
+    "公共交通": {
+      "pronunciation": "gōnggòng jiāotōng",
+      "type": "noun",
+      "user_language": "public transportation"
+    },
+    "绿色": {
+      "pronunciation": "lǜsè",
+      "type": "adjective",
+      "user_language": "green; environmentally friendly"
+    },
+    "诞生": {
+      "pronunciation": "dànshēng",
+      "type": "verb",
+      "user_language": "to be born, to come into being"
+    },
+    "欧洲": {
+      "pronunciation": "Ōuzhōu",
+      "type": "proper noun",
+      "user_language": "Europe"
+    },
+    "汽车": {
+      "pronunciation": "qìchē",
+      "type": "noun",
+      "user_language": "car, automobile"
+    },
+    "空气": {
+      "pronunciation": "kōngqì",
+      "type": "noun",
+      "user_language": "air"
+    },
+    "严重": {
+      "pronunciation": "yánzhòng",
+      "type": "adjective",
+      "user_language": "serious, severe"
+    },
+    "提出": {
+      "pronunciation": "tíchū",
+      "type": "verb",
+      "user_language": "to put forward, to propose"
+    },
+    "支持": {
+      "pronunciation": "zhīchí",
+      "type": "verb/noun",
+      "user_language": "to support; support"
+    },
+    "开展": {
+      "pronunciation": "kāizhǎn",
+      "type": "verb",
+      "user_language": "to launch, to carry out"
+    },
+    "活动": {
+      "pronunciation": "huódòng",
+      "type": "noun",
+      "user_language": "activity"
+    },
+    "世界性": {
+      "pronunciation": "shìjièxìng",
+      "type": "adjective",
+      "user_language": "worldwide, global"
+    },
+    "建议": {
+      "pronunciation": "jiànyì",
+      "type": "verb/noun",
+      "user_language": "to suggest; suggestion"
+    },
+    "选择": {
+      "pronunciation": "xuǎnzé",
+      "type": "verb",
+      "user_language": "to choose, to select"
+    },
+    "公交": {
+      "pronunciation": "gōngjiāo",
+      "type": "noun",
+      "user_language": "public transportation (abbreviation)"
+    },
+    "利用": {
+      "pronunciation": "lìyòng",
+      "type": "verb",
+      "user_language": "to use, to utilize"
+    },
+    "道路": {
+      "pronunciation": "dàolù",
+      "type": "noun",
+      "user_language": "road, path"
+    },
+    "减少": {
+      "pronunciation": "jiǎnshǎo",
+      "type": "verb",
+      "user_language": "to reduce, to decrease"
+    },
+    "了解": {
+      "pronunciation": "liǎojiě",
+      "type": "verb",
+      "user_language": "to understand, to know"
+    },
+    "过多": {
+      "pronunciation": "guòduō",
+      "type": "adjective",
+      "user_language": "too much, excessive"
+    },
+    "城市": {
+      "pronunciation": "chéngshì",
+      "type": "noun",
+      "user_language": "city"
+    },
+    "环境": {
+      "pronunciation": "huánjìng",
+      "type": "noun",
+      "user_language": "environment"
+    },
+    "危害": {
+      "pronunciation": "wēihài",
+      "type": "noun/verb",
+      "user_language": "harm, danger; to harm"
+    },
+    "环保": {
+      "pronunciation": "huánbǎo",
+      "type": "noun",
+      "user_language": "environmental protection (abbreviation)"
+    },
+    "加重": {
+      "pronunciation": "jiāzhòng",
+      "type": "verb",
+      "user_language": "to worsen, to aggravate"
+    },
+    "同时": {
+      "pronunciation": "tóngshí",
+      "type": "adverb/conjunction",
+      "user_language": "at the same time, meanwhile"
+    },
+    "应": {
+      "pronunciation": "yīng",
+      "type": "auxiliary verb",
+      "user_language": "should, ought to (written language)"
+    },
+    "保护": {
+      "pronunciation": "bǎohù",
+      "type": "verb",
+      "user_language": "to protect"
+    },
+    "生活方式": {
+      "pronunciation": "shēnghuó fāngshì",
+      "type": "noun",
+      "user_language": "lifestyle, way of life"
+    },
+    "息息相关": {
+      "pronunciation": "xīxī xiāngguān",
+      "type": "idiom",
+      "user_language": "closely related"
+    },
+    "随手": {
+      "pronunciation": "suíshǒu",
+      "type": "adverb",
+      "user_language": "conveniently, in passing"
+    },
+    "做到": {
+      "pronunciation": "zuòdào",
+      "type": "verb",
+      "user_language": "to achieve, to accomplish"
+    },
+    "水龙头": {
+      "pronunciation": "shuǐlóngtóu",
+      "type": "noun",
+      "user_language": "faucet, tap"
+    },
+    "一直": {
+      "pronunciation": "yīzhí",
+      "type": "adverb",
+      "user_language": "continuously, always"
+    },
+    "洗手": {
+      "pronunciation": "xǐshǒu",
+      "type": "verb",
+      "user_language": "to wash hands"
+    },
+    "洗澡": {
+      "pronunciation": "xǐzǎo",
+      "type": "verb",
+      "user_language": "to take a bath/shower"
+    },
+    "洗衣服": {
+      "pronunciation": "xǐ yīfu",
+      "type": "verb phrase",
+      "user_language": "to wash clothes"
+    },
+    "关灯": {
+      "pronunciation": "guān dēng",
+      "type": "verb phrase",
+      "user_language": "to turn off the light"
+    },
+    "电费": {
+      "pronunciation": "diànfèi",
+      "type": "noun",
+      "user_language": "electricity bill"
+    },
+    "度": {
+      "pronunciation": "dù",
+      "type": "measure word",
+      "user_language": "degree; kilowatt-hour (for electricity)"
+    },
+    "有害": {
+      "pronunciation": "yǒuhài",
+      "type": "adjective",
+      "user_language": "harmful"
+    },
+    "气体": {
+      "pronunciation": "qìtǐ",
+      "type": "noun",
+      "user_language": "gas"
+    },
+    "擦地": {
+      "pronunciation": "cā dì",
+      "type": "verb phrase",
+      "user_language": "to mop the floor"
+    },
+    "冲厕所": {
+      "pronunciation": "chōng cèsuǒ",
+      "type": "verb phrase",
+      "user_language": "to flush the toilet"
+    },
+    "塑料袋": {
+      "pronunciation": "sùliàodài",
+      "type": "noun",
+      "user_language": "plastic bag"
+    },
+    "自备": {
+      "pronunciation": "zìbèi",
+      "type": "verb",
+      "user_language": "to bring one's own"
+    },
+    "袋子": {
+      "pronunciation": "dàizi",
+      "type": "noun",
+      "user_language": "bag"
+    },
+    "食用": {
+      "pronunciation": "shíyòng",
+      "type": "verb",
+      "user_language": "to eat, to consume"
+    },
+    "野生动物": {
+      "pronunciation": "yěshēng dòngwù",
+      "type": "noun",
+      "user_language": "wild animal"
+    },
+    "穿": {
+      "pronunciation": "chuān",
+      "type": "verb",
+      "user_language": "to wear"
+    },
+    "毛皮": {
+      "pronunciation": "máopí",
+      "type": "noun",
+      "user_language": "fur, pelt"
+    },
+    "选购": {
+      "pronunciation": "xuǎngòu",
+      "type": "verb",
+      "user_language": "to select and purchase"
+    },
+    "农药": {
+      "pronunciation": "nóngyào",
+      "type": "noun",
+      "user_language": "pesticide"
+    },
+    "新鲜": {
+      "pronunciation": "xīnxiān",
+      "type": "adjective",
+      "user_language": "fresh"
+    },
+    "果蔬": {
+      "pronunciation": "guǒshū",
+      "type": "noun",
+      "user_language": "fruits and vegetables (abbreviation)"
+    },
+    "包装": {
+      "pronunciation": "bāozhuāng",
+      "type": "noun/verb",
+      "user_language": "packaging; to pack"
+    },
+    "绿色食品": {
+      "pronunciation": "lǜsè shípǐn",
+      "type": "noun",
+      "user_language": "green food, organic food"
+    },
+    "标识": {
+      "pronunciation": "biāoshí",
+      "type": "noun",
+      "user_language": "mark, sign, logo"
+    },
+    "工具": {
+      "pronunciation": "gōngjù",
+      "type": "noun",
+      "user_language": "tool, instrument"
+    },
+    "汽油": {
+      "pronunciation": "qìyóu",
+      "type": "noun",
+      "user_language": "gasoline, petrol"
+    },
+    "尾气": {
+      "pronunciation": "wěiqì",
+      "type": "noun",
+      "user_language": "exhaust gas, emissions"
+    },
+    "公共场所": {
+      "pronunciation": "gōnggòng chǎngsuǒ",
+      "type": "noun",
+      "user_language": "public place"
+    },
+    "室内": {
+      "pronunciation": "shìnèi",
+      "type": "noun",
+      "user_language": "indoor, interior"
+    },
+    "吸烟": {
+      "pronunciation": "xīyān",
+      "type": "verb",
+      "user_language": "to smoke"
+    },
+    "做好": {
+      "pronunciation": "zuòhǎo",
+      "type": "verb",
+      "user_language": "to do well, to complete"
+    },
+    "垃圾分类": {
+      "pronunciation": "lājī fēnlèi",
+      "type": "noun",
+      "user_language": "garbage sorting, waste classification"
+    },
+    "种类": {
+      "pronunciation": "zhǒnglèi",
+      "type": "noun",
+      "user_language": "type, kind, category"
+    },
+    "分开": {
+      "pronunciation": "fēnkāi",
+      "type": "verb",
+      "user_language": "to separate, to divide"
+    },
+    "放": {
+      "pronunciation": "fàng",
+      "type": "verb",
+      "user_language": "to put, to place"
+    },
+    "当作": {
+      "pronunciation": "dàngzuò",
+      "type": "verb",
+      "user_language": "to regard as, to treat as"
+    },
+    "有用": {
+      "pronunciation": "yǒuyòng",
+      "type": "adjective",
+      "user_language": "useful"
+    },
+    "混装": {
+      "pronunciation": "hùnzhuāng",
+      "type": "verb",
+      "user_language": "to mix and pack together"
+    },
+    "土地": {
+      "pronunciation": "tǔdì",
+      "type": "noun",
+      "user_language": "land, soil"
+    },
+    "照顾": {
+      "pronunciation": "zhàogu",
+      "type": "verb",
+      "user_language": "to take care of, to look after"
+    },
+    "附近": {
+      "pronunciation": "fùjìn",
+      "type": "noun",
+      "user_language": "nearby, vicinity"
+    },
+    "树": {
+      "pronunciation": "shù",
+      "type": "noun",
+      "user_language": "tree"
+    },
+    "定期": {
+      "pronunciation": "dìngqī",
+      "type": "adverb",
+      "user_language": "regularly, periodically"
+    },
+    "浇水": {
+      "pronunciation": "jiāoshuǐ",
+      "type": "verb",
+      "user_language": "to water (plants)"
+    },
+    "家庭": {
+      "pronunciation": "jiātíng",
+      "type": "noun",
+      "user_language": "family, household"
+    },
+    "一员": {
+      "pronunciation": "yī yuán",
+      "type": "noun",
+      "user_language": "a member"
+    }
+  },
+  "grammar": {
+    "随着": {
+      "title": "随着…… - along with, as",
+      "pattern": "随着 + Noun/Phrase, Result",
+      "explanation": "Used to indicate that something changes as another thing changes",
+      "examples": [
+        {
+          "chinese": "随着春天的到来，天气暖和起来了。",
+          "pronunciation": "Suízhe chūntiān de dàolái, tiānqì nuǎnhuo qǐlái le.",
+          "translation": "As spring arrives, the weather is getting warmer."
+        },
+        {
+          "chinese": "随着年龄的增长，人的身体会发生很多变化。",
+          "pronunciation": "Suízhe niánlíng de zēngzhǎng, rén de shēntǐ huì fāshēng hěnduō biànhuà.",
+          "translation": "As age increases, people's bodies undergo many changes."
+        },
+        {
+          "chinese": "随着城市的发展，环境污染问题也在加重。",
+          "pronunciation": "Suízhe chéngshì de fāzhǎn, huánjìng wūrǎn wèntí yě zài jiāzhòng.",
+          "translation": "As cities develop, environmental pollution problems are also worsening."
+        }
+      ]
+    },
+    "已-written": {
+      "title": "已 (yǐ) - already (written language)",
+      "explanation": "Written Chinese adverb meaning '已经' (already). More formal.",
+      "examples": [
+        {
+          "chinese": "比赛已结束。",
+          "pronunciation": "Bǐsài yǐ jiéshù.",
+          "translation": "The competition has already ended."
+        },
+        {
+          "chinese": "这项工作已完成。",
+          "pronunciation": "Zhè xiàng gōngzuò yǐ wánchéng.",
+          "translation": "This work has already been completed."
+        }
+      ]
+    },
+    "单-written": {
+      "title": "单 (dān) - only, merely (written language)",
+      "explanation": "Written Chinese adverb meaning '只' (only). More formal.",
+      "examples": [
+        {
+          "chinese": "这部动画片不单孩子喜欢，大人也爱看。",
+          "pronunciation": "Zhè bù dònghuàpiàn bù dān háizi xǐhuan, dàrén yě ài kàn.",
+          "translation": "Not only do children like this cartoon, adults love watching it too."
+        },
+        {
+          "chinese": "我每个月的花费很多，单交通费就要几百元。",
+          "pronunciation": "Wǒ měi gè yuè de huāfèi hěnduō, dān jiāotōngfèi jiù yào jǐ bǎi yuán.",
+          "translation": "My monthly expenses are high; transportation alone costs several hundred yuan."
+        }
+      ]
+    }
+  },
+  "texts": [
+    {
+      "id": "main-text",
+      "title": "世界无车日 (World Car Free Day)",
+      "type": "main",
+      "content": "有这样一个笑话：\"早上上班时间，你在北京朝阳区；坐一小时的车，你在朝阳区；再坐一小时，你还是在朝阳区。\"\n\n交通拥堵是很多大城市的通病。为解决交通拥堵问题、便利人们出行，交通管理部门想了很多办法，比如：修建地铁、发展自行车租车服务、控制汽车数量等。每年9月22日\"世界无车日\"前后，北京市交管部门都会鼓励市民不开车，用步行、自行车、公共交通等绿色方式出行。\n\n\"无车日\"最早诞生于1998年的法国。那时候欧洲的很多城市里，汽车带来的空气污染、噪声污染越来越严重。1998年9月22日，法国一些年轻人最先提出\"In Town, Without My Car!\"，这个说法得到了人们的支持。后来世界上的很多城市都开展了\"无车日\"活动，\"无车日\"慢慢成了世界性的活动。\"世界无车日\"活动鼓励绿色出行，建议市民们更多地选择公交出行，一是为了更好地利用道路资源，减少交通拥堵，二是让人们了解汽车过多对城市环境的危害，提高人们的环保意识。",
+      "wordCount": 376,
+      "questions": [
+        {
+          "question": "第1段的笑话说的是什么情况？",
+          "type": "open",
+          "answer": "交通拥堵，坐车很久还在同一个地方"
+        },
+        {
+          "question": "根据第2段，为解决交通拥堵问题，交通管理部门想了哪些办法？",
+          "type": "open",
+          "answer": "修建地铁、发展自行车租车服务、控制汽车数量"
+        },
+        {
+          "question": "根据第3段，\"世界无车日\"是怎样诞生的？",
+          "type": "open",
+          "answer": "1998年法国，因为汽车带来的污染严重，年轻人提出无车日，得到支持"
+        },
+        {
+          "question": "根据课文，说说\"绿色出行\"是什么意思。",
+          "type": "open",
+          "answer": "用步行、自行车、公共交通等环保方式出行"
+        }
+      ]
+    },
+    {
+      "id": "environmental-tips",
+      "title": "环保小贴士 (Environmental Tips)",
+      "type": "extensive",
+      "content": "随着城市的发展，环境污染问题也在加重。人们在抱怨城市空气越来越糟糕的同时，也应意识到环境的保护和每个人的生活方式息息相关。\n\n下面是生活中可以随手做到的几件环保小事。\n\n一、随手关水龙头，不要一直开着水龙头洗手、洗澡、洗衣服。\n\n二、随手关灯，这不只是为了节约电费，每节约一度电，空气中就会减少很多有害的气体。\n\n三、洗衣服后的水可以擦地或冲厕所等。\n\n四、买东西时不用塑料袋，出门购物带上自备的袋子。\n\n五、不食用野生动物，不穿野生动物毛皮做的衣服。\n\n六、选购不用农药的新鲜果蔬，买包装上有\"绿色食品\"标识的食品。\n\n七、多用公共交通工具，这样既可以节约汽油，又可以减少汽车尾气带来的空气污染。\n\n八、公共场所、室内工作场所、公共交通工具内不吸烟。\n\n九、做好垃圾分类，不同种类的垃圾分开放。分装垃圾是把垃圾当作有用的资源，混装的垃圾会污染土地和空气。\n\n十、照顾附近的一棵树，定期给它浇水，把它当作家庭里的一员。",
+      "wordCount": 404,
+      "questions": [
+        {
+          "question": "从衣、食、住、行这四个方面说说身边的环保小事",
+          "type": "open",
+          "answer": "衣：不穿野生动物毛皮；食：买绿色食品；住：节约水电，垃圾分类；行：多用公共交通"
+        },
+        {
+          "question": "关于身边的环保小事，文中没有提到的是：",
+          "type": "multiple_choice",
+          "options": ["A用温水煮饭", "B节约用水用电", "C生活垃圾分类", "D不在公共场所吸烟"],
+          "correctAnswer": "A用温水煮饭"
+        }
+      ]
+    }
+  ],
+  "exercises": [
+    {
+      "type": "abbreviations",
+      "title": "缩略语练习 (Abbreviations)",
+      "description": "Practice recognizing and forming Chinese abbreviations",
+      "questions": [
+        {
+          "question": "北京大学",
+          "answer": "北大"
+        },
+        {
+          "question": "电子邮件",
+          "answer": "电邮"
+        },
+        {
+          "question": "空中小姐",
+          "answer": "空姐"
+        },
+        {
+          "question": "奥林匹克运动会",
+          "answer": "奥运会"
+        },
+        {
+          "question": "交通管理部门",
+          "answer": "交管部门"
+        },
+        {
+          "question": "城市居民",
+          "answer": "市民"
+        },
+        {
+          "question": "公共交通",
+          "answer": "公交"
+        },
+        {
+          "question": "环境保护",
+          "answer": "环保"
+        }
+      ]
+    }
+  ]
+}
diff --git a/docs/architecture.md b/docs/architecture.md
new file mode 100644
index 0000000..9b1e1d9
--- /dev/null
+++ b/docs/architecture.md
@@ -0,0 +1,259 @@
+# Architecture Guide
+
+## 🏗️ Core Principles
+
+### 1. Single Responsibility
+Each module has exactly one purpose. No mixing of concerns.
+
+### 2. Event-Driven Communication
+All inter-module communication happens through EventBus. Zero direct dependencies.
+
+```javascript
+// ❌ BAD - Direct access
+const gameManager = window.app.modules.gameManager;
+gameManager.startGame();
+
+// ✅ GOOD - EventBus
+eventBus.emit('game:start', { difficulty: 'medium' });
+```
+
+### 3. Sealed Modules
+Modules cannot be modified after creation using `Object.seal()`.
+
+```javascript
+constructor() {
+    super('ModuleName');
+    this._privateState = {};
+    Object.seal(this); // Prevents adding/removing properties
+}
+```
+
+### 4. WeakMap Private State
+Internal data is completely inaccessible from outside.
+
+```javascript
+const privateData = new WeakMap();
+
+class SecureModule {
+    constructor() {
+        privateData.set(this, {
+            apiKey: 'secret',
+            internalState: {}
+        });
+    }
+
+    getPrivateData() {
+        return privateData.get(this);
+    }
+}
+```
+
+### 5. Dependency Injection
+No globals. Everything injected through constructor.
+
+```javascript
+class GameModule extends Module {
+    constructor(name, dependencies, config) {
+        super(name, ['eventBus', 'renderer']);
+
+        // Dependencies injected, not accessed globally
+        this._eventBus = dependencies.eventBus;
+        this._renderer = dependencies.renderer;
+        this._config = config;
+    }
+}
+```
+
+## 🔄 Module Lifecycle
+
+```
+1. REGISTRATION  → Application.js modules array
+2. LOADING       → ModuleLoader imports class
+3. INSTANTIATION → new Module(name, deps, config)
+4. INITIALIZATION → module.init() called
+5. READY         → Module emits 'ready' event
+6. DESTRUCTION   → module.destroy() on cleanup
+```
+
+## 📦 System Components
+
+### Core Layer (`src/core/`)
+
+**Module.js** - Abstract base class
+- WeakMap private state
+- Lifecycle management (init/destroy)
+- State validation
+- Abstract enforcement
+
+**EventBus.js** - Event communication
+- Module registration required
+- Event history tracking
+- Cross-module isolation
+- Memory leak prevention
+
+**ModuleLoader.js** - Dependency injection
+- Topological sort for dependencies
+- Circular dependency detection
+- Proper initialization order
+- Dynamic import system
+
+**Router.js** - Navigation system
+- Route guards
+- Middleware execution
+- State management
+- History integration
+
+**Application.js** - Bootstrap system
+- Auto-initialization
+- Module registration
+- Lifecycle coordination
+- Debug panel
+
+### DRS Layer (`src/DRS/`)
+
+**Exercise Modules** (`exercise-modules/`)
+- VocabularyModule - Flashcard spaced repetition
+- TextAnalysisModule - AI text comprehension
+- GrammarAnalysisModule - AI grammar correction
+- TranslationModule - AI translation validation
+- OpenResponseModule - Free-form AI evaluation
+
+**Services** (`services/`)
+- IAEngine - Multi-provider AI system
+- LLMValidator - Answer validation
+- ContentLoader - Content generation
+- ProgressTracker - Progress management
+- PrerequisiteEngine - Prerequisite checking
+
+**Interfaces** (`interfaces/`)
+- StrictInterface - Base enforcement class
+- ProgressItemInterface - Progress tracking contract
+- ProgressSystemInterface - Progress system contract
+- DRSExerciseInterface - Exercise module contract
+
+### Games Layer (`src/games/`)
+
+Independent game modules for entertainment (NOT part of DRS).
+- FlashcardLearning.js - Standalone flashcard game
+- Future games...
+
+## 🚫 Separation Rules
+
+### DRS vs Games - NEVER MIX
+
+**DRS** = Educational exercises with strict interfaces
+**Games** = Entertainment with different architecture
+
+```javascript
+// ❌ FORBIDDEN - DRS importing games
+import FlashcardLearning from '../games/FlashcardLearning.js';
+
+// ✅ CORRECT - DRS uses its own modules
+import VocabularyModule from './exercise-modules/VocabularyModule.js';
+```
+
+## 🔒 Security Layers
+
+1. **Object.seal()** - Prevents property addition/deletion
+2. **Object.freeze()** - Prevents prototype modification
+3. **WeakMap** - Internal state hidden
+4. **Abstract enforcement** - Missing methods throw errors
+5. **Validation at boundaries** - All inputs validated
+
+## 📊 Data Flow
+
+```
+User Action
+    ↓
+UI Component
+    ↓
+Event Emission (EventBus)
+    ↓
+Module Event Handler
+    ↓
+Business Logic
+    ↓
+State Update
+    ↓
+Event Emission (state changed)
+    ↓
+UI Update
+```
+
+## 🎯 Module Types
+
+### 1. Core Modules
+System-level functionality. Never modify these.
+
+### 2. Game Modules
+Entertainment-focused, extend Module base class.
+
+### 3. DRS Exercise Modules
+Educational exercises, implement DRSExerciseInterface.
+
+### 4. Service Modules
+Support functionality (AI, progress, content).
+
+### 5. UI Components
+Reusable interface elements (future phase).
+
+## ⚡ Performance Targets
+
+- **<100ms** module loading time
+- **<50ms** event propagation time
+- **<200ms** application startup time
+- **Zero** memory leaks in module lifecycle
+
+## 🧪 Testing Strategy
+
+1. **Unit Tests** - Individual module behavior
+2. **Integration Tests** - Module communication via EventBus
+3. **Interface Tests** - Contract compliance (ImplementationValidator)
+4. **E2E Tests** - Complete user flows
+
+## 📋 Architecture Checklist
+
+For every new feature:
+- [ ] Single responsibility maintained
+- [ ] EventBus for all communication
+- [ ] No direct module dependencies
+- [ ] Proper dependency injection
+- [ ] Object.seal() applied
+- [ ] Abstract methods implemented
+- [ ] Lifecycle methods complete
+- [ ] Memory cleanup in destroy()
+- [ ] Interface compliance validated
+- [ ] No global variables used
+
+## 🔍 Debug Tools
+
+```javascript
+// Application status
+window.app.getStatus()
+
+// Module inspection
+window.app.getCore().moduleLoader.getStatus()
+
+// Event history
+window.app.getCore().eventBus.getEventHistory()
+
+// Navigate programmatically
+window.app.getCore().router.navigate('/path')
+```
+
+## 🚨 Common Violations
+
+1. **Direct module access** → Use EventBus
+2. **Global variables** → Use dependency injection
+3. **Mixed responsibilities** → Split into separate modules
+4. **No cleanup** → Implement destroy() properly
+5. **Hardcoded dependencies** → Declare in constructor
+6. **Missing validation** → Validate all inputs
+7. **Modifying core** → Extend, don't modify
+
+## 📖 Further Reading
+
+- `docs/creating-new-module.md` - Module creation guide
+- `docs/interfaces.md` - Interface system details
+- `docs/progress-system.md` - Progress tracking guide
+- `README.md` - Project overview
diff --git a/docs/creating-new-module.md b/docs/creating-new-module.md
new file mode 100644
index 0000000..e60f1f5
--- /dev/null
+++ b/docs/creating-new-module.md
@@ -0,0 +1,312 @@
+# Creating New Modules
+
+## 🎮 Game Module Template
+
+### Basic Structure
+
+```javascript
+import Module from '../core/Module.js';
+
+class GameName extends Module {
+    constructor(name, dependencies, config) {
+        super(name, ['eventBus']); // Declare dependencies
+
+        // Validate dependencies
+        if (!dependencies.eventBus) {
+            throw new Error('GameName requires EventBus dependency');
+        }
+
+        this._eventBus = dependencies.eventBus;
+        this._config = config;
+
+        Object.seal(this); // Prevent modification
+    }
+
+    async init() {
+        this._validateNotDestroyed();
+
+        // Set up event listeners
+        this._eventBus.on('game:start', this._handleStart.bind(this), this.name);
+
+        this._setInitialized();
+    }
+
+    async destroy() {
+        this._validateNotDestroyed();
+
+        // Cleanup: remove event listeners, DOM elements, timers
+        this._eventBus.off('game:start', this._handleStart, this.name);
+
+        this._setDestroyed();
+    }
+
+    // Private methods
+    _handleStart(event) {
+        this._validateInitialized();
+        // Game logic here
+    }
+}
+
+export default GameName;
+```
+
+### Registration in Application.js
+
+```javascript
+modules: [
+    {
+        name: 'gameName',
+        path: './games/GameName.js',
+        dependencies: ['eventBus'],
+        config: {
+            difficulty: 'medium',
+            scoreToWin: 100
+        }
+    }
+]
+```
+
+## 📋 DRS Exercise Module Template
+
+### Using DRSExerciseInterface
+
+```javascript
+import DRSExerciseInterface from '../DRS/interfaces/DRSExerciseInterface.js';
+
+class MyExercise extends DRSExerciseInterface {
+    constructor() {
+        super('MyExercise');
+
+        // Internal state
+        this.score = 0;
+        this.attempts = 0;
+        this.startTime = null;
+        this.container = null;
+    }
+
+    // ⚠️ REQUIRED - Initialize exercise
+    async init(config, content) {
+        this.config = config;
+        this.content = content;
+        this.startTime = Date.now();
+
+        // Validate content
+        if (!content || !content.question) {
+            throw new Error('MyExercise requires content with question');
+        }
+    }
+
+    // ⚠️ REQUIRED - Render UI
+    async render(container) {
+        this.container = container;
+
+        container.innerHTML = `
+            <div class="exercise-container">
+                <h2>${this.content.question}</h2>
+                <input type="text" id="answer-input" />
+                <button id="submit-btn">Submit</button>
+            </div>
+        `;
+
+        // Event listeners
+        container.querySelector('#submit-btn').addEventListener('click', () => {
+            const answer = container.querySelector('#answer-input').value;
+            this.handleUserInput('submit', { answer });
+        });
+    }
+
+    // ⚠️ REQUIRED - Clean up
+    async destroy() {
+        if (this.container) {
+            this.container.innerHTML = '';
+        }
+    }
+
+    // ⚠️ REQUIRED - Validate answer
+    async validate(userAnswer) {
+        this.attempts++;
+
+        const isCorrect = userAnswer.toLowerCase() === this.content.correctAnswer.toLowerCase();
+        const score = isCorrect ? 100 - (this.attempts - 1) * 10 : 0;
+
+        return {
+            isCorrect,
+            score: Math.max(score, 0),
+            feedback: isCorrect ? 'Correct!' : 'Try again',
+            explanation: `The correct answer is: ${this.content.correctAnswer}`
+        };
+    }
+
+    // ⚠️ REQUIRED - Get results
+    getResults() {
+        return {
+            score: this.score,
+            attempts: this.attempts,
+            timeSpent: Date.now() - this.startTime,
+            completed: this.score > 0,
+            details: {
+                question: this.content.question,
+                correctAnswer: this.content.correctAnswer
+            }
+        };
+    }
+
+    // ⚠️ REQUIRED - Handle user input
+    handleUserInput(event, data) {
+        if (event === 'submit') {
+            this.validate(data.answer).then(result => {
+                this.score = result.score;
+                this.displayFeedback(result);
+            });
+        }
+    }
+
+    // ⚠️ REQUIRED - Mark as completed
+    async markCompleted(results) {
+        // Save to progress system
+        await window.app.getCore().progressTracker.markExerciseCompleted(
+            'my-exercise',
+            this.content.id,
+            results
+        );
+    }
+
+    // ⚠️ REQUIRED - Get progress
+    getProgress() {
+        return {
+            percentage: this.score > 0 ? 100 : 0,
+            currentStep: 1,
+            totalSteps: 1,
+            itemsCompleted: this.score > 0 ? 1 : 0,
+            itemsTotal: 1
+        };
+    }
+
+    // ⚠️ REQUIRED - Get exercise type
+    getExerciseType() {
+        return 'my-exercise';
+    }
+
+    // ⚠️ REQUIRED - Get exercise config
+    getExerciseConfig() {
+        return {
+            type: 'my-exercise',
+            difficulty: this.config?.difficulty || 'medium',
+            estimatedTime: 120, // seconds
+            prerequisites: [],
+            metadata: {
+                hasAI: false,
+                requiresInternet: false
+            }
+        };
+    }
+
+    // Helper methods
+    displayFeedback(result) {
+        const feedbackDiv = this.container.querySelector('.feedback') ||
+                           document.createElement('div');
+        feedbackDiv.className = 'feedback';
+        feedbackDiv.textContent = result.feedback;
+
+        if (!this.container.querySelector('.feedback')) {
+            this.container.appendChild(feedbackDiv);
+        }
+    }
+}
+
+export default MyExercise;
+```
+
+## 📊 Progress Item Template
+
+### Using ProgressItemInterface
+
+```javascript
+import ProgressItemInterface from '../DRS/interfaces/ProgressItemInterface.js';
+
+class MyCustomItem extends ProgressItemInterface {
+    constructor(id, metadata) {
+        super('my-custom-item', id, metadata);
+    }
+
+    // ⚠️ REQUIRED - Validate item data
+    validate() {
+        if (!this.metadata.requiredField) {
+            throw new Error('MyCustomItem requires requiredField in metadata');
+        }
+        return true;
+    }
+
+    // ⚠️ REQUIRED - Convert to JSON
+    serialize() {
+        return {
+            ...this._getBaseSerialization(),
+            customData: this.metadata.custom,
+            timestamp: Date.now()
+        };
+    }
+
+    // ⚠️ REQUIRED - Return item weight
+    getWeight() {
+        return ProgressItemInterface.WEIGHTS['my-custom-item'] || 5;
+    }
+
+    // ⚠️ REQUIRED - Check prerequisites
+    canComplete(userProgress) {
+        // Check if user has completed prerequisites
+        const prerequisite = this.metadata.prerequisite;
+        if (prerequisite) {
+            return userProgress.hasCompleted(prerequisite);
+        }
+        return true;
+    }
+}
+
+export default MyCustomItem;
+```
+
+## ✅ Checklist for New Modules
+
+### For Game Modules
+- [ ] Extends `Module` base class
+- [ ] Validates dependencies in constructor
+- [ ] Uses `Object.seal(this)` at end of constructor
+- [ ] Implements `init()` and calls `_setInitialized()`
+- [ ] Implements `destroy()` and calls `_setDestroyed()`
+- [ ] Uses EventBus for all communication
+- [ ] No direct access to other modules
+- [ ] Registered in `Application.js` modules array
+
+### For DRS Exercise Modules
+- [ ] Extends `DRSExerciseInterface`
+- [ ] Implements all 10 required methods
+- [ ] Validates content in `init()`
+- [ ] Cleans up in `destroy()`
+- [ ] Returns correct format from `validate()`
+- [ ] Integrates with progress system
+- [ ] Tested with ImplementationValidator
+
+### For Progress Items
+- [ ] Extends `ProgressItemInterface`
+- [ ] Implements all 4 required methods
+- [ ] Validates data correctly
+- [ ] Returns proper weight
+- [ ] Checks prerequisites properly
+- [ ] Added to ImplementationValidator
+
+## 🚨 Common Mistakes to Avoid
+
+1. **Forgetting Object.seal()** - Module can be modified externally
+2. **Not validating dependencies** - Module fails at runtime
+3. **Direct module access** - Use EventBus instead
+4. **Missing required methods** - Red screen error at startup
+5. **Not cleaning up** - Memory leaks on destroy
+6. **Hardcoded paths** - Use dynamic content loading
+7. **Skipping ImplementationValidator** - Interface violations not caught
+
+## 📚 Examples in Codebase
+
+- **Game Module**: `src/games/FlashcardLearning.js`
+- **DRS Exercise**: `src/DRS/exercise-modules/VocabularyModule.js`
+- **Progress Item**: `src/DRS/services/ProgressItemInterface.js`
+- **Validation**: `src/DRS/services/ImplementationValidator.js`
diff --git a/docs/interfaces.md b/docs/interfaces.md
new file mode 100644
index 0000000..cea1e48
--- /dev/null
+++ b/docs/interfaces.md
@@ -0,0 +1,314 @@
+# Interface System (C++ Style)
+
+## 🎯 Philosophy
+
+Like C++ header files (.h), we enforce **strict interfaces** that MUST be implemented. Any missing method = **RED SCREEN ERROR** at startup.
+
+## 📦 Interface Hierarchy
+
+```
+StrictInterface (base)
+├── ProgressItemInterface           # For progress tracking items
+│   ├── VocabularyDiscoveryItem
+│   ├── VocabularyMasteryItem
+│   └── Content Items (Phrase, Dialog, Text, Audio, Image, Grammar)
+│
+├── ProgressSystemInterface         # For progress systems
+│   ├── ProgressTracker
+│   └── PrerequisiteEngine
+│
+└── DRSExerciseInterface           # For exercise modules
+    ├── VocabularyModule
+    ├── TextAnalysisModule
+    ├── GrammarAnalysisModule
+    ├── TranslationModule
+    └── OpenResponseModule
+```
+
+## 🔥 1. StrictInterface (Base)
+
+**Location**: `src/DRS/interfaces/StrictInterface.js`
+
+**Purpose**: Ultra-strict base class with visual error enforcement.
+
+**Features**:
+- Validates implementation at construction
+- Full-screen red error overlay if method missing
+- Sound alert in dev mode
+- Screen shake animation
+- Impossible to ignore
+
+**Error Display**:
+```
+┌─────────────────────────────────────────────┐
+│                                             │
+│           🔥 FATAL ERROR 🔥                │
+│                                             │
+│      Implementation Missing                 │
+│                                             │
+│  Class: VocabularyModule                   │
+│  Missing Method: validate()                │
+│                                             │
+│  ❌ MUST implement all interface methods   │
+│                                             │
+│     [ DISMISS (Fix Required!) ]            │
+│                                             │
+└─────────────────────────────────────────────┘
+```
+
+## 📋 2. ProgressItemInterface
+
+**Location**: `src/DRS/interfaces/ProgressItemInterface.js`
+
+**Purpose**: Contract for all progress tracking items.
+
+### Required Methods (4)
+
+```javascript
+validate()           // Validate item data
+serialize()          // Convert to JSON
+getWeight()          // Return item weight for progress calculation
+canComplete(state)   // Check prerequisites
+```
+
+### Implementations
+
+| Class | Weight | Prerequisites |
+|-------|--------|---------------|
+| VocabularyDiscoveryItem | 1 | None |
+| VocabularyMasteryItem | 1 | Discovered |
+| PhraseItem | 6 | Vocabulary mastered |
+| DialogItem | 12 | Vocabulary mastered |
+| TextItem | 15 | Vocabulary mastered |
+| AudioItem | 12 | Vocabulary mastered |
+| ImageItem | 6 | Vocabulary discovered |
+| GrammarItem | 6 | Vocabulary discovered |
+
+### Example Implementation
+
+```javascript
+import ProgressItemInterface from '../interfaces/ProgressItemInterface.js';
+
+class MyItem extends ProgressItemInterface {
+    constructor(id, metadata) {
+        super('my-item', id, metadata);
+    }
+
+    // ⚠️ REQUIRED
+    validate() {
+        if (!this.metadata.requiredField) {
+            throw new Error('Missing requiredField');
+        }
+        return true;
+    }
+
+    // ⚠️ REQUIRED
+    serialize() {
+        return {
+            ...this._getBaseSerialization(),
+            customData: this.metadata.custom
+        };
+    }
+
+    // ⚠️ REQUIRED
+    getWeight() {
+        return ProgressItemInterface.WEIGHTS['my-item'] || 5;
+    }
+
+    // ⚠️ REQUIRED
+    canComplete(userProgress) {
+        // Check prerequisites
+        return true;
+    }
+}
+```
+
+## 🔧 3. ProgressSystemInterface
+
+**Location**: `src/DRS/interfaces/ProgressSystemInterface.js`
+
+**Purpose**: Contract for all progress management systems.
+
+### Required Methods (17)
+
+**Vocabulary Tracking:**
+- `markWordDiscovered(word, metadata)`
+- `markWordMastered(word, metadata)`
+- `isWordDiscovered(word)`
+- `isWordMastered(word)`
+
+**Content Tracking:**
+- `markPhraseCompleted(id, metadata)`
+- `markDialogCompleted(id, metadata)`
+- `markTextCompleted(id, metadata)`
+- `markAudioCompleted(id, metadata)`
+- `markImageCompleted(id, metadata)`
+- `markGrammarCompleted(id, metadata)`
+
+**Prerequisites:**
+- `canComplete(itemType, itemId, context)`
+
+**Progress:**
+- `getProgress(chapterId)`
+
+**Persistence:**
+- `saveProgress(bookId, chapterId)`
+- `loadProgress(bookId, chapterId)`
+
+**Utility:**
+- `reset(bookId, chapterId)`
+
+### Implementations
+
+- **ProgressTracker** - Weight-based progress with items
+- **PrerequisiteEngine** - Prerequisite checking and mastery tracking
+
+## 🎮 4. DRSExerciseInterface
+
+**Location**: `src/DRS/interfaces/DRSExerciseInterface.js`
+
+**Purpose**: Contract for all DRS exercise modules.
+
+### Required Methods (10)
+
+**Lifecycle:**
+- `init(config, content)` - Initialize exercise
+- `render(container)` - Render UI
+- `destroy()` - Clean up
+
+**Exercise Logic:**
+- `validate(userAnswer)` - Validate answer
+  - Returns: `{ isCorrect, score, feedback, explanation }`
+- `getResults()` - Get results
+  - Returns: `{ score, attempts, timeSpent, completed, details }`
+- `handleUserInput(event, data)` - Handle user input
+
+**Progress Tracking:**
+- `markCompleted(results)` - Mark as completed
+- `getProgress()` - Get progress
+  - Returns: `{ percentage, currentStep, totalSteps, itemsCompleted, itemsTotal }`
+
+**Metadata:**
+- `getExerciseType()` - Return exercise type string
+- `getExerciseConfig()` - Return config object
+  - Returns: `{ type, difficulty, estimatedTime, prerequisites, metadata }`
+
+### Implementations
+
+- **VocabularyModule** - Flashcard spaced repetition
+- **TextAnalysisModule** - AI-powered text comprehension
+- **GrammarAnalysisModule** - AI grammar correction
+- **TranslationModule** - AI translation validation
+- **OpenResponseModule** - Free-form AI evaluation
+
+## ✅ 5. ImplementationValidator
+
+**Location**: `src/DRS/services/ImplementationValidator.js`
+
+**Purpose**: Validate ALL implementations at application startup.
+
+### Validation Phases
+
+```javascript
+🔍 VALIDATING DRS IMPLEMENTATIONS...
+
+📦 PART 1: Validating Progress Items...
+  ✅ VocabularyDiscoveryItem - OK
+  ✅ VocabularyMasteryItem - OK
+  ✅ PhraseItem - OK
+  ✅ DialogItem - OK
+  ✅ TextItem - OK
+  ✅ AudioItem - OK
+  ✅ ImageItem - OK
+  ✅ GrammarItem - OK
+
+🔧 PART 2: Validating Progress Systems...
+  ✅ ProgressTracker - OK
+  ✅ PrerequisiteEngine - OK
+
+🎮 PART 3: Validating DRS Exercise Modules...
+  ✅ VocabularyModule - OK
+  ✅ TextAnalysisModule - OK
+  ✅ GrammarAnalysisModule - OK
+  ✅ TranslationModule - OK
+  ✅ OpenResponseModule - OK
+
+✅ ALL DRS IMPLEMENTATIONS VALID
+```
+
+### Integration with Application.js
+
+```javascript
+// At startup (lines 55-62)
+console.log('🔍 Validating progress item implementations...');
+const { default: ImplementationValidator } = await import('./DRS/services/ImplementationValidator.js');
+const isValid = await ImplementationValidator.validateAll();
+
+if (!isValid) {
+    throw new Error('❌ Implementation validation failed - check console for details');
+}
+```
+
+## 🚨 Enforcement Rules
+
+### NON-NEGOTIABLE
+
+1. ❌ **Missing method** → RED SCREEN ERROR → App refuses to start
+2. ❌ **Wrong signature** → Runtime error on call
+3. ❌ **Wrong return format** → Runtime error on usage
+4. ✅ **All methods implemented** → App starts normally
+
+### Validation Happens
+
+- ✅ At application startup (before any UI renders)
+- ✅ On module registration
+- ✅ At interface instantiation
+
+## ✨ Benefits
+
+1. 🛡️ **Impossible to forget implementation** - Visual error forces fix
+2. 📋 **Self-documenting** - Interface defines exact contract
+3. 🔒 **Type safety** - Like TypeScript but enforced at runtime
+4. 🧪 **Testable** - Can mock interfaces for unit tests
+5. 🔄 **Maintainable** - Adding new method updates all implementations
+
+## 📋 Interface Compliance Checklist
+
+Before creating a new implementation:
+
+- [ ] Identified correct interface to extend
+- [ ] Implemented ALL required methods
+- [ ] Correct method signatures
+- [ ] Correct return formats
+- [ ] Validation logic in place
+- [ ] Added to ImplementationValidator
+- [ ] Tested with validation at startup
+- [ ] Documentation updated
+
+## 🔍 Testing Your Implementation
+
+```javascript
+// Manual test in console
+const validator = await import('./DRS/services/ImplementationValidator.js');
+const result = await validator.default.validateAll();
+console.log(result); // true if valid, throws error otherwise
+```
+
+## 🚧 Adding New Interface Methods
+
+When adding a new method to an interface:
+
+1. Update the interface class
+2. Update ALL implementations
+3. Update ImplementationValidator
+4. Update this documentation
+5. Test with validation
+6. Commit changes
+
+**Result**: All implementations will show RED SCREEN ERROR until updated.
+
+## 📖 Further Reading
+
+- `docs/creating-new-module.md` - How to create new modules
+- `docs/progress-system.md` - Progress tracking details
+- `README.md` - Project overview
diff --git a/docs/progress-system.md b/docs/progress-system.md
new file mode 100644
index 0000000..0eb5182
--- /dev/null
+++ b/docs/progress-system.md
@@ -0,0 +1,268 @@
+# Progress System
+
+## 🎯 Core Philosophy
+
+**FUNDAMENTAL RULE**: Every piece of content is a trackable progress item with strict validation and type safety.
+
+## 🏗️ Pedagogical Flow
+
+```
+1. DISCOVERY → 2. MASTERY → 3. APPLICATION
+   (passive)      (active)       (context)
+```
+
+### Flow Rules (NON-NEGOTIABLE)
+
+- ❌ **NO Flashcards on undiscovered words** - Must discover first
+- ❌ **NO Text exercises on unmastered vocabulary** - Must master first
+- ✅ **Always check prerequisites before ANY exercise**
+- ✅ **Form vocabulary lists on-the-fly** from next exercise content
+
+## 📦 Progress Item Types & Weights
+
+| Type | Weight | Prerequisites |
+|------|--------|---------------|
+| vocabulary-discovery | 1 | None |
+| vocabulary-mastery | 1 | Must be discovered |
+| phrase | 6 | Vocabulary mastered |
+| dialog | 12 | Vocabulary mastered |
+| text | 15 | Vocabulary mastered |
+| audio | 12 | Vocabulary mastered |
+| image | 6 | Vocabulary discovered |
+| grammar | 6 | Vocabulary discovered |
+
+**Total for 1 vocabulary word** = 2 points (1 discovery + 1 mastery)
+
+## 📈 Progress Calculation
+
+### Chapter Analysis
+
+When loading a chapter:
+
+1. **Scans ALL content** (vocabulary, phrases, dialogs, texts, etc.)
+2. **Creates progress items** for each piece
+3. **Calculates total weight** (sum of all item weights)
+4. **Stores item registry** for tracking
+
+**Example Chapter:**
+- 171 vocabulary words → 342 points (171×2: discovery + mastery)
+- 75 phrases → 450 points (75×6)
+- 6 dialogs → 72 points (6×12)
+- 3 lessons → 45 points (3×15)
+- **TOTAL: 909 points**
+
+### Progress Formula
+
+```javascript
+percentage = (completedWeight / totalWeight) × 100
+
+// Example:
+// - Discovered 50 words = 50 points
+// - Mastered 20 words = 20 points
+// - Completed 3 phrases = 18 points (3×6)
+// - Completed 1 dialog = 12 points
+// Total completed = 100 points
+// Progress = (100 / 909) × 100 = 11%
+```
+
+### Breakdown Display
+
+```javascript
+{
+  percentage: 11,
+  completedWeight: 100,
+  totalWeight: 909,
+  breakdown: {
+    'vocabulary-discovery': { count: 50, weight: 50 },
+    'vocabulary-mastery': { count: 20, weight: 20 },
+    'phrase': { count: 3, weight: 18 },
+    'dialog': { count: 1, weight: 12 }
+  }
+}
+```
+
+## 🎯 Smart Vocabulary Prerequisites
+
+### OLD Approach (Wrong)
+Force all 171 words upfront based on arbitrary percentages.
+
+### NEW Approach (Correct)
+Analyze next content → extract words → check user status → force only needed words.
+
+### Example Flow
+
+```javascript
+// Next exercise: Dialog "Academic Conference"
+// Words in dialog: methodology, hypothesis, analysis, paradigm, framework
+
+// User status check:
+// - methodology: never seen → Discovery needed
+// - hypothesis: discovered, not mastered → Mastery needed
+// - analysis: mastered → Skip
+// - paradigm: never seen → Discovery needed
+// - framework: discovered, not mastered → Mastery needed
+
+// Smart system creates:
+// 1. Discovery module: [methodology, paradigm] (2 words)
+// 2. Mastery module: [hypothesis, framework] (2 words)
+// 3. Then allow dialog exercise
+```
+
+### Benefits
+
+- **Targeted Learning** - Only learn words actually needed
+- **Context-Driven** - Vocabulary tied to real content usage
+- **Efficient Progress** - No time wasted on irrelevant words
+- **Better Retention** - Words learned in context of upcoming usage
+- **Smart Adaptation** - UI accurately reflects what's happening
+
+## 🔧 Key Components
+
+### 1. ProgressItemInterface
+Abstract base with strict validation for all progress items.
+
+**Location**: `src/DRS/interfaces/ProgressItemInterface.js`
+
+**Methods**:
+- `validate()` - Validate item data
+- `serialize()` - Convert to JSON
+- `getWeight()` - Return item weight
+- `canComplete(state)` - Check prerequisites
+
+### 2. ProgressTracker
+Manages state, marks completion, saves progress.
+
+**Location**: `src/DRS/services/ProgressTracker.js`
+
+**Key Methods**:
+- `markWordDiscovered(word, metadata)`
+- `markWordMastered(word, metadata)`
+- `markContentCompleted(type, id, metadata)`
+- `getProgress(chapterId)`
+- `saveProgress(bookId, chapterId)`
+- `loadProgress(bookId, chapterId)`
+
+### 3. PrerequisiteEngine
+Checks prerequisites and enforces pedagogical flow.
+
+**Location**: `src/DRS/services/PrerequisiteEngine.js`
+
+**Key Methods**:
+- `canComplete(itemType, itemId, context)`
+- `getUnmetPrerequisites(itemType, itemId)`
+- `enforcePrerequisites(exerciseConfig)`
+
+### 4. ContentDependencyAnalyzer
+Analyzes content and extracts vocabulary dependencies.
+
+**Location**: `src/DRS/services/ContentDependencyAnalyzer.js`
+
+**Key Methods**:
+- `analyzeContentDependencies(nextContent, vocabularyModule)`
+- `extractWordsFromContent(content)`
+- `findMissingWords(wordsInContent, vocabularyWords)`
+
+## 📊 UI Integration
+
+### Progress Display
+
+```
+Chapter Progress: 11% (100/909 points)
+
+✅ Vocabulary Discovery: 50/171 words (50pts)
+✅ Vocabulary Mastery: 20/171 words (20pts)
+✅ Phrases: 3/75 (18pts)
+✅ Dialogs: 1/6 (12pts)
+⬜ Texts: 0/3 (0/45pts)
+```
+
+### Smart Guide Updates
+
+```
+🔍 Analyzing next exercise: Dialog "Academic Conference"
+📚 4 words needed (2 discovery, 2 mastery)
+🎯 Starting Vocabulary Discovery for: methodology, paradigm
+```
+
+## ✅ Validation Checklist
+
+**Before ANY exercise can run:**
+
+- [ ] Prerequisites analyzed for next specific content
+- [ ] Missing words identified
+- [ ] Discovery forced for never-seen words
+- [ ] Mastery forced for seen-but-not-mastered words
+- [ ] Progress item created with correct weight
+- [ ] Completion properly tracked and saved
+- [ ] Total progress recalculated
+
+**If ANY step fails → Clear error message, app stops gracefully**
+
+## 🚨 Error Prevention
+
+### Compile-Time (Startup)
+- Interface validation via ImplementationValidator
+- Method implementation checks
+- Weight configuration validation
+
+### Runtime
+- Prerequisite enforcement before exercises
+- State consistency checks
+- Progress calculation validation
+
+### Visual Feedback
+- Red screen for missing implementations
+- Clear prerequisite errors
+- Progress breakdown always visible
+
+## 🔍 Debug Commands
+
+```javascript
+// Get current progress
+window.app.getCore().progressTracker.getProgress('chapter-1')
+
+// Check if word discovered
+window.app.getCore().progressTracker.isWordDiscovered('methodology')
+
+// Check if word mastered
+window.app.getCore().progressTracker.isWordMastered('hypothesis')
+
+// Check prerequisites
+window.app.getCore().prerequisiteEngine.canComplete('dialog', 'dialog-3')
+
+// Get unmet prerequisites
+window.app.getCore().prerequisiteEngine.getUnmetPrerequisites('text', 'lesson-1')
+```
+
+## 📋 Adding New Progress Item Types
+
+1. Create new class extending `ProgressItemInterface`
+2. Implement all 4 required methods
+3. Add weight to `WEIGHTS` constant
+4. Add to `ImplementationValidator`
+5. Update `ProgressTracker` tracking methods
+6. Update UI components
+7. Test with validation
+
+## 🧪 Testing Progress System
+
+```javascript
+// Test progress calculation
+const tracker = window.app.getCore().progressTracker;
+
+// Mark some progress
+await tracker.markWordDiscovered('test', {});
+await tracker.markWordMastered('test', {});
+
+// Check progress
+const progress = tracker.getProgress('chapter-1');
+console.log(progress);
+
+// Should show updated percentage and breakdown
+```
+
+## 📖 Further Reading
+
+- `docs/interfaces.md` - Interface system details
+- `docs/creating-new-module.md` - Module creation guide
+- `README.md` - Project overview
diff --git a/src/DRS/exercise-modules/VocabularyModule.js b/src/DRS/exercise-modules/VocabularyModule.js
index 59ac984..d51c941 100644
--- a/src/DRS/exercise-modules/VocabularyModule.js
+++ b/src/DRS/exercise-modules/VocabularyModule.js
@@ -528,9 +528,11 @@ class VocabularyModule extends DRSExerciseInterface {
         card.innerHTML = `
             <div class="word-card">
                 <div class="word-display">
-                    <h3 class="target-word">${currentWord.word}</h3>
+                    <h3 class="target-word clickable" id="target-word-tts" title="Click to hear pronunciation">
+                        ${currentWord.word}
+                    </h3>
                     ${this.config.showPronunciation && currentWord.pronunciation ?
-                        `<div class="pronunciation">[${currentWord.pronunciation}]</div>` : ''}
+                        `<div class="pronunciation" id="pronunciation-display">[${currentWord.pronunciation}]</div>` : ''}
                     <div class="word-type">${currentWord.type || 'word'}</div>
                 </div>
 
@@ -545,11 +547,11 @@ class VocabularyModule extends DRSExerciseInterface {
                 </div>
 
                 <div class="revealed-answer" id="revealed-answer" style="display: none;">
-                    <div class="correct-translation">
+                    <div class="correct-translation clickable" id="answer-tts" title="Click to hear pronunciation">
                         <strong>Correct Answer:</strong> ${currentWord.cleanTranslation}
                     </div>
                     ${this.config.showPronunciation && currentWord.pronunciation ?
-                        `<div class="pronunciation-text">[${currentWord.pronunciation}]</div>` : ''}
+                        `<div class="pronunciation-text" id="pronunciation-reveal">[${currentWord.pronunciation}]</div>` : ''}
                 </div>
             </div>
         `;
@@ -567,6 +569,14 @@ class VocabularyModule extends DRSExerciseInterface {
         document.getElementById('reveal-btn').onclick = this._handleRevealAnswer;
         document.getElementById('submit-btn').onclick = this._handleUserInput;
 
+        // Add click listener on the word itself for TTS
+        const targetWord = document.getElementById('target-word-tts');
+        if (targetWord) {
+            targetWord.onclick = () => {
+                this._handleTTS();
+                this._highlightPronunciation();
+            };
+        }
 
         // Allow Enter key to submit
         const input = document.getElementById('translation-input');
@@ -625,9 +635,19 @@ class VocabularyModule extends DRSExerciseInterface {
             answerSection.style.display = 'none';
             this.isRevealed = true;
 
+            // Add click listener on revealed answer for TTS
+            const answerTTS = document.getElementById('answer-tts');
+            if (answerTTS) {
+                answerTTS.onclick = () => {
+                    this._handleTTS();
+                    this._highlightPronunciation();
+                };
+            }
+
             // Auto-play TTS when answer is revealed
             setTimeout(() => {
                 this._handleTTS();
+                this._highlightPronunciation();
             }, 100); // Quick delay to let the answer appear
 
             // Don't mark as incorrect yet - wait for user self-assessment
@@ -780,22 +800,25 @@ class VocabularyModule extends DRSExerciseInterface {
 
                 const utterance = new SpeechSynthesisUtterance(text);
 
-                // Configure voice settings
-                utterance.lang = options.lang || 'en-US';
+                // Get language from chapter data, fallback to options or en-US
+                const chapterLanguage = this.currentExerciseData?.language || 'en-US';
+                utterance.lang = options.lang || chapterLanguage;
                 utterance.rate = options.rate || 0.8;
                 utterance.pitch = options.pitch || 1;
                 utterance.volume = options.volume || 1;
 
-                // Try to find a suitable voice
+                // Try to find a suitable voice for the language
                 const voices = window.speechSynthesis.getVoices();
                 if (voices.length > 0) {
-                    // Prefer English voices
-                    const englishVoice = voices.find(voice =>
-                        voice.lang.startsWith('en') && voice.default
-                    ) || voices.find(voice => voice.lang.startsWith('en'));
+                    // Find voice matching the chapter language
+                    const langPrefix = chapterLanguage.split('-')[0]; // e.g., "zh" from "zh-CN"
+                    const matchingVoice = voices.find(voice =>
+                        voice.lang.startsWith(langPrefix) && voice.default
+                    ) || voices.find(voice => voice.lang.startsWith(langPrefix));
 
-                    if (englishVoice) {
-                        utterance.voice = englishVoice;
+                    if (matchingVoice) {
+                        utterance.voice = matchingVoice;
+                        console.log('🔊 Using voice:', matchingVoice.name, matchingVoice.lang);
                     }
                 }
 
@@ -852,6 +875,22 @@ class VocabularyModule extends DRSExerciseInterface {
         }
     }
 
+    _highlightPronunciation() {
+        // Highlight pronunciation when TTS is played
+        const pronunciation = document.getElementById('pronunciation-display') ||
+                            document.getElementById('pronunciation-reveal');
+
+        if (pronunciation) {
+            // Add highlight class
+            pronunciation.classList.add('pronunciation-highlight');
+
+            // Remove highlight after animation
+            setTimeout(() => {
+                pronunciation.classList.remove('pronunciation-highlight');
+            }, 2000);
+        }
+    }
+
     _showGroupResults() {
         const resultsContainer = document.getElementById('group-results');
         const card = document.getElementById('vocabulary-card');
@@ -1039,10 +1078,33 @@ class VocabularyModule extends DRSExerciseInterface {
                 font-weight: bold;
             }
 
+            .target-word.clickable {
+                cursor: pointer;
+                transition: all 0.2s ease;
+            }
+
+            .target-word.clickable:hover {
+                color: #667eea;
+                transform: scale(1.05);
+            }
+
             .pronunciation {
                 font-style: italic;
                 color: #666;
                 margin-bottom: 5px;
+                transition: all 0.3s ease;
+            }
+
+            .pronunciation-highlight {
+                color: #667eea !important;
+                font-weight: bold;
+                font-size: 1.2em;
+                animation: pulse 0.5s ease-in-out;
+            }
+
+            @keyframes pulse {
+                0%, 100% { transform: scale(1); }
+                50% { transform: scale(1.1); }
             }
 
             .word-type {
@@ -1089,9 +1151,22 @@ class VocabularyModule extends DRSExerciseInterface {
                 margin-bottom: 5px;
             }
 
+            .correct-translation.clickable {
+                cursor: pointer;
+                transition: all 0.2s ease;
+                padding: 5px;
+                border-radius: 4px;
+            }
+
+            .correct-translation.clickable:hover {
+                background-color: #d4edda;
+                transform: scale(1.02);
+            }
+
             .pronunciation-text {
                 font-style: italic;
                 color: #666;
+                transition: all 0.3s ease;
             }
 
             .exercise-controls {
diff --git a/src/gameHelpers/MarioEducational/PhysicsEngine.js b/src/gameHelpers/MarioEducational/PhysicsEngine.js
new file mode 100644
index 0000000..94ac22e
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/PhysicsEngine.js
@@ -0,0 +1,343 @@
+/**
+ * PhysicsEngine.js
+ * Helper for physics simulation, collision detection, and movement
+ * Handles Mario physics, enemy physics, particles, and camera
+ */
+
+export class PhysicsEngine {
+    /**
+     * Update Mario movement based on key inputs
+     * @param {Object} mario - Mario object
+     * @param {Object} keys - Key states object
+     * @param {Object} config - Game config with moveSpeed and jumpForce
+     * @param {boolean} isCelebrating - If true, disable movement
+     * @param {Function} playSound - Sound callback for jump
+     */
+    static updateMarioMovement(mario, keys, config, isCelebrating, playSound) {
+        // Don't update movement during celebration
+        if (isCelebrating) return;
+
+        // Horizontal movement
+        if (keys['ArrowLeft'] || keys['KeyA']) {
+            mario.velocityX = -config.moveSpeed;
+            mario.facing = 'left';
+        } else if (keys['ArrowRight'] || keys['KeyD']) {
+            mario.velocityX = config.moveSpeed;
+            mario.facing = 'right';
+        } else {
+            mario.velocityX *= 0.8; // Friction
+        }
+
+        // Jumping
+        if ((keys['ArrowUp'] || keys['KeyW'] || keys['Space']) && mario.onGround) {
+            mario.velocityY = config.jumpForce;
+            mario.onGround = false;
+            if (playSound) playSound('jump');
+        }
+    }
+
+    /**
+     * Update Mario physics (gravity and position)
+     * @param {Object} mario - Mario object
+     * @param {Object} config - Game config with gravity
+     * @param {Object} level - Current level data
+     * @param {boolean} levelCompleted - If level is completed
+     * @param {Function} onFallOff - Callback when Mario falls off world
+     */
+    static updateMarioPhysics(mario, config, level, levelCompleted, onFallOff) {
+        // Apply gravity
+        mario.velocityY += config.gravity;
+
+        // Update position
+        mario.x += mario.velocityX;
+        mario.y += mario.velocityY;
+
+        // Prevent going off left edge
+        if (mario.x < 0) {
+            mario.x = 0;
+        }
+
+        // Stop Mario at finish line during celebration
+        if (mario.x > level.endX && levelCompleted) {
+            mario.x = level.endX;
+            mario.velocityX = 0;
+        }
+
+        // Check if Mario fell off the world
+        if (mario.y > config.canvasHeight + 100) {
+            if (onFallOff) onFallOff();
+        }
+    }
+
+    /**
+     * Update enemy movement and AI
+     * @param {Array} enemies - Array of enemies
+     * @param {Array} walls - Array of walls
+     * @param {Array} platforms - Array of platforms
+     * @param {number} levelWidth - Level width
+     * @param {boolean} isCelebrating - If true, disable updates
+     */
+    static updateEnemies(enemies, walls, platforms, levelWidth, isCelebrating) {
+        // Don't update enemies during celebration
+        if (isCelebrating) return;
+
+        enemies.forEach(enemy => {
+            // Store old position for collision detection
+            const oldX = enemy.x;
+            enemy.x += enemy.velocityX;
+
+            // Check wall collisions
+            const hitWall = walls.some(wall => {
+                return enemy.x < wall.x + wall.width &&
+                       enemy.x + enemy.width > wall.x &&
+                       enemy.y < wall.y + wall.height &&
+                       enemy.y + enemy.height > wall.y;
+            });
+
+            if (hitWall) {
+                // Reverse position and direction
+                enemy.x = oldX;
+                enemy.velocityX *= -1;
+                console.log(`🧱 Enemy hit wall, reversing direction`);
+            }
+
+            // Simple AI: reverse direction at platform edges
+            const platform = platforms.find(p =>
+                enemy.x >= p.x - 10 && enemy.x <= p.x + p.width + 10 &&
+                enemy.y >= p.y - enemy.height - 5 && enemy.y <= p.y + 5
+            );
+
+            if (!platform || enemy.x <= 0 || enemy.x >= levelWidth) {
+                enemy.velocityX *= -1;
+            }
+        });
+    }
+
+    /**
+     * Check all collisions (platforms, walls, enemies, etc.)
+     * @param {Object} mario - Mario object
+     * @param {Object} gameState - All game entities
+     * @param {Object} callbacks - Callbacks for various collision events
+     */
+    static checkCollisions(mario, gameState, callbacks) {
+        const {
+            platforms, questionBlocks, enemies, walls, catapults,
+            piranhaPlants, boulders
+        } = gameState;
+
+        const {
+            onQuestionBlock, onEnemyDefeat, onMarioDeath, onAddParticles
+        } = callbacks;
+
+        // Platform collisions
+        mario.onGround = false;
+
+        platforms.forEach(platform => {
+            if (this.isColliding(mario, platform)) {
+                // Check if Mario is landing on top
+                if (mario.velocityY > 0 && mario.y + mario.height - mario.velocityY <= platform.y + 5) {
+                    mario.y = platform.y - mario.height;
+                    mario.velocityY = 0;
+                    mario.onGround = true;
+                }
+                // Hit from below
+                else if (mario.velocityY < 0 && mario.y - mario.velocityY >= platform.y + platform.height - 5) {
+                    mario.y = platform.y + platform.height;
+                    mario.velocityY = 0;
+                }
+                // Side collision
+                else {
+                    if (mario.velocityX > 0) {
+                        mario.x = platform.x - mario.width;
+                    } else if (mario.velocityX < 0) {
+                        mario.x = platform.x + platform.width;
+                    }
+                    mario.velocityX = 0;
+                }
+            }
+        });
+
+        // Boulder collisions (grounded boulders only)
+        boulders.forEach(boulder => {
+            if (boulder.hasLanded && this.isColliding(mario, boulder)) {
+                console.log(`🪨 Mario hit by grounded boulder - restarting level`);
+                if (onMarioDeath) onMarioDeath();
+            }
+        });
+
+        // Question block collisions
+        questionBlocks.forEach(block => {
+            if (!block.hit && this.isColliding(mario, block)) {
+                // Check if Mario hit from below
+                if (mario.velocityY < 0 && mario.y < block.y + block.height) {
+                    if (onQuestionBlock) onQuestionBlock(block);
+                }
+                // Solid collision (treat as platform)
+                else if (mario.velocityY > 0) {
+                    mario.y = block.y - mario.height;
+                    mario.velocityY = 0;
+                    mario.onGround = true;
+                }
+            }
+        });
+
+        // Wall collisions
+        walls.forEach(wall => {
+            if (this.isColliding(mario, wall)) {
+                // Side collision
+                if (mario.velocityX > 0) {
+                    mario.x = wall.x - mario.width;
+                } else if (mario.velocityX < 0) {
+                    mario.x = wall.x + wall.width;
+                }
+                mario.velocityX = 0;
+
+                // Top/bottom collision
+                if (mario.velocityY > 0) {
+                    mario.y = wall.y - mario.height;
+                    mario.velocityY = 0;
+                    mario.onGround = true;
+                } else if (mario.velocityY < 0) {
+                    mario.y = wall.y + wall.height;
+                    mario.velocityY = 0;
+                }
+            }
+        });
+
+        // Catapult collisions (solid obstacles)
+        catapults.forEach(catapult => {
+            if (this.isColliding(mario, catapult)) {
+                // Treat catapults as solid platforms
+                if (mario.velocityY > 0) {
+                    mario.y = catapult.y - mario.height;
+                    mario.velocityY = 0;
+                    mario.onGround = true;
+                }
+            }
+        });
+
+        // Enemy collisions
+        enemies.forEach((enemy, index) => {
+            if (this.isColliding(mario, enemy)) {
+                // Check if Mario jumped on enemy
+                if (mario.velocityY > 0 && mario.y < enemy.y + enemy.height / 2) {
+                    // Enemy defeated
+                    mario.velocityY = -8; // Bounce
+                    if (onEnemyDefeat) onEnemyDefeat(index);
+                    if (onAddParticles) onAddParticles(enemy.x, enemy.y, '#FFD700');
+                } else {
+                    // Mario hit by enemy
+                    console.log(`👾 Mario hit by enemy - restarting level`);
+                    if (onMarioDeath) onMarioDeath();
+                }
+            }
+        });
+
+        // Piranha Plant collisions
+        piranhaPlants.forEach(plant => {
+            if (!plant.flattened && this.isColliding(mario, plant)) {
+                // Check if Mario jumped on plant
+                if (mario.velocityY > 0 && mario.y < plant.y + plant.height / 2) {
+                    // Plant flattened
+                    plant.flattened = true;
+                    plant.flattenedTimer = 120; // Flattened for 2 seconds
+                    mario.velocityY = -8; // Bounce
+                    if (onAddParticles) onAddParticles(plant.x, plant.y, '#228B22');
+                    console.log(`🌸 Mario flattened piranha plant`);
+                } else {
+                    // Mario hit by plant
+                    console.log(`🌸 Mario hit by piranha plant - restarting level`);
+                    if (onMarioDeath) onMarioDeath();
+                }
+            }
+
+            // Check if stepping on flattened plant
+            if (plant.flattened && this.isColliding(mario, plant)) {
+                mario.onGround = true;
+            }
+        });
+    }
+
+    /**
+     * Rectangle-Rectangle collision detection
+     * @param {Object} rect1 - First rectangle
+     * @param {Object} rect2 - Second rectangle
+     * @returns {boolean} - True if colliding
+     */
+    static isColliding(rect1, rect2) {
+        return rect1.x < rect2.x + rect2.width &&
+               rect1.x + rect1.width > rect2.x &&
+               rect1.y < rect2.y + rect2.height &&
+               rect1.y + rect1.height > rect2.y;
+    }
+
+    /**
+     * Update camera to follow Mario
+     * @param {Object} camera - Camera object with x, y
+     * @param {Object} mario - Mario object
+     * @param {number} canvasWidth - Canvas width
+     */
+    static updateCamera(camera, mario, canvasWidth) {
+        // Camera follows Mario horizontally, centered
+        camera.x = mario.x - canvasWidth / 2 + mario.width / 2;
+        camera.y = 0; // Fixed vertical camera
+    }
+
+    /**
+     * Create particle effects
+     * @param {number} x - X position
+     * @param {number} y - Y position
+     * @param {string} color - Particle color
+     * @param {Array} particles - Particles array to add to
+     * @param {number} count - Number of particles to create
+     */
+    static addParticles(x, y, color, particles, count = 10) {
+        for (let i = 0; i < count; i++) {
+            particles.push({
+                x: x,
+                y: y,
+                velocityX: (Math.random() - 0.5) * 8,
+                velocityY: (Math.random() - 0.5) * 8,
+                life: 1.0,
+                decay: 0.02,
+                size: 4,
+                color: color
+            });
+        }
+    }
+
+    /**
+     * Create small particle burst
+     * @param {number} x - X position
+     * @param {number} y - Y position
+     * @param {string} color - Particle color
+     * @param {Array} particles - Particles array to add to
+     */
+    static addSmallParticles(x, y, color, particles) {
+        this.addParticles(x, y, color, particles, 5);
+    }
+
+    /**
+     * Update all particles
+     * @param {Array} particles - Array of particles
+     * @returns {Array} - Updated particles array (with dead particles removed)
+     */
+    static updateParticles(particles) {
+        const updatedParticles = [];
+
+        particles.forEach(particle => {
+            particle.x += particle.velocityX;
+            particle.y += particle.velocityY;
+            particle.velocityY += 0.3; // Gravity
+            particle.life -= particle.decay;
+
+            if (particle.life > 0) {
+                updatedParticles.push(particle);
+            }
+        });
+
+        return updatedParticles;
+    }
+}
+
+export default PhysicsEngine;
diff --git a/src/gameHelpers/MarioEducational/README.md b/src/gameHelpers/MarioEducational/README.md
new file mode 100644
index 0000000..d3b26ed
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/README.md
@@ -0,0 +1,123 @@
+# MarioEducational Game Helpers
+
+Modular helper classes to reduce the size of the main MarioEducational.js file.
+
+## 📁 Structure
+
+```
+gameHelpers/MarioEducational/
+├── SentenceGenerator.js (386 lines) - Educational sentence generation with proper grammar
+├── SoundSystem.js (271 lines) - Web Audio API sound management
+├── Renderer.js (625 lines) - All rendering methods with camera translation
+├── enemies/
+│   ├── PiranhaPlant.js (133 lines) - Piranha plant enemy logic
+│   ├── Catapult.js (347 lines) - Catapult/Onager + Boulders + Stones
+│   ├── FlyingEye.js (187 lines) - Flying eye chase AI + dash attacks
+│   ├── Boss.js (254 lines) - Colossal boss + turrets + minions
+│   └── Projectile.js (147 lines) - Projectile management
+└── README.md
+```
+
+## 📊 Statistics
+
+### Helpers Created
+- **Total Files**: 9 files
+- **Total Lines**: 2,350 lines of modular, reusable code
+- **Categories**: Sentences, Sound, Rendering, Enemies (5 types)
+
+### Main File Reduction
+- **Before**: 3,901 lines / 156 KB
+- **After helpers**: ~1,900 lines / ~75 KB (estimated after full integration)
+- **Reduction**: ~51% smaller, ~2,000 lines extracted
+
+## 🎯 Usage
+
+### Sentence Generation
+```javascript
+import { sentenceGenerator } from './gameHelpers/MarioEducational/SentenceGenerator.js';
+
+const sentence = sentenceGenerator.generateSentence('apple', {
+    type: 'noun',
+    user_language: 'pomme'
+});
+// Returns: { english: "I see an apple.", translation: "pomme - I see an **apple**." }
+```
+
+### Sound System
+```javascript
+import { soundSystem } from './gameHelpers/MarioEducational/SoundSystem.js';
+
+soundSystem.initialize();
+soundSystem.play('jump');
+soundSystem.play('enemy_defeat', 0.5); // Volume 0-1
+```
+
+### Rendering
+```javascript
+import { renderer } from './gameHelpers/MarioEducational/Renderer.js';
+
+const gameState = {
+    mario, camera, platforms, enemies, /* ... */
+};
+renderer.render(ctx, gameState, config);
+```
+
+### Enemies
+```javascript
+import PiranhaPlant from './gameHelpers/MarioEducational/enemies/PiranhaPlant.js';
+import Catapult from './gameHelpers/MarioEducational/enemies/Catapult.js';
+import FlyingEye from './gameHelpers/MarioEducational/enemies/FlyingEye.js';
+import Boss from './gameHelpers/MarioEducational/enemies/Boss.js';
+import Projectile from './gameHelpers/MarioEducational/enemies/Projectile.js';
+
+// Generation
+const plants = PiranhaPlant.generate(level, difficulty);
+const catapults = Catapult.generate(level, levelIndex, levelWidth, canvasHeight);
+const eyes = FlyingEye.generate(level, difficulty);
+const { boss, turrets } = Boss.generate(level, levelWidth, canvasHeight);
+
+// Update
+PiranhaPlant.update(plants, mario, projectiles, playSound);
+Catapult.update(catapults, mario, boulders, stones, playSound);
+FlyingEye.update(eyes, mario, playSound);
+Boss.update(boss, turrets, mario, projectiles, flyingEyes, playSound);
+
+// Projectiles
+const updatedProjectiles = Projectile.update(projectiles, mario, platforms, walls, levelWidth, onMarioHit, onObstacleHit);
+```
+
+## ✨ Benefits
+
+1. **Modularity**: Each system is self-contained and testable
+2. **Reusability**: Helpers can be used in other games
+3. **Maintainability**: Smaller files are easier to understand and modify
+4. **Performance**: No performance impact, pure code organization
+5. **Scalability**: Easy to add new enemy types or features
+
+## 🔧 Architecture Principles
+
+- **Single Responsibility**: Each helper has one clear purpose
+- **Stateless**: Most helpers are stateless (except SoundSystem)
+- **Dependency Injection**: Helpers receive data as parameters
+- **No Side Effects**: Helpers don't modify global state
+- **Pure Functions**: Most methods are pure (same input → same output)
+
+## 📚 Documentation
+
+Each helper file contains detailed JSDoc comments explaining:
+- Method parameters and return values
+- Usage examples
+- Edge cases and assumptions
+- Performance considerations
+
+## 🚀 Future Improvements
+
+- Extract LevelGenerator (~1500 lines) - largest remaining opportunity
+- Extract PhysicsEngine (~400 lines) - collision detection and movement
+- Add unit tests for each helper
+- Create EnemyFactory for unified enemy creation
+- Add TypeScript definitions for better IDE support
+
+---
+
+**Result**: Clean, maintainable, and scalable game architecture! 🎮
diff --git a/src/gameHelpers/MarioEducational/Renderer.js b/src/gameHelpers/MarioEducational/Renderer.js
new file mode 100644
index 0000000..21299f8
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/Renderer.js
@@ -0,0 +1,625 @@
+/**
+ * Renderer.js
+ * Helper for rendering all game elements (Mario, enemies, platforms, effects, etc.)
+ * Handles canvas drawing with proper layering and camera translation
+ */
+
+export class Renderer {
+    constructor() {
+        // No internal state - all rendering is stateless based on game data
+    }
+
+    /**
+     * Main render method - orchestrates all rendering
+     * @param {CanvasRenderingContext2D} ctx - Canvas 2D context
+     * @param {Object} gameState - Current game state with all entities
+     * @param {Object} config - Game configuration
+     */
+    render(ctx, gameState, config) {
+        // Clear canvas
+        ctx.clearRect(0, 0, config.canvasWidth, config.canvasHeight);
+
+        // Render background (no camera translation)
+        this.renderBackground(ctx, gameState.camera, config);
+
+        // Save context for camera translation
+        ctx.save();
+        ctx.translate(-gameState.camera.x, -gameState.camera.y);
+
+        // Render world elements (with camera translation)
+        this.renderPlatforms(ctx, gameState.platforms);
+        this.renderQuestionBlocks(ctx, gameState.questionBlocks);
+        this.renderEnemies(ctx, gameState.enemies);
+        this.renderWalls(ctx, gameState.walls);
+
+        // Advanced level elements
+        if (gameState.piranhaPlants) this.renderPiranhaPlants(ctx, gameState.piranhaPlants);
+        if (gameState.projectiles) this.renderProjectiles(ctx, gameState.projectiles);
+
+        // Level 4+ elements
+        if (gameState.catapults) this.renderCatapults(ctx, gameState.catapults);
+        if (gameState.boulders) this.renderBoulders(ctx, gameState.boulders);
+        if (gameState.stones) this.renderStones(ctx, gameState.stones);
+
+        // Level 5+ elements
+        if (gameState.flyingEyes) this.renderFlyingEyes(ctx, gameState.flyingEyes);
+
+        // Level 6 boss elements
+        if (gameState.boss) this.renderBoss(ctx, gameState.boss);
+
+        // Castle
+        if (gameState.castle) this.renderCastle(ctx, gameState.castle);
+
+        // Finish line
+        if (gameState.finishLine) this.renderFinishLine(ctx, gameState.finishLine, gameState.currentLevel);
+
+        // Mario
+        this.renderMario(ctx, gameState.mario);
+
+        // Particles
+        if (gameState.particles) this.renderParticles(ctx, gameState.particles);
+
+        // Debug hitboxes
+        if (gameState.debugMode) {
+            this.renderDebugHitboxes(ctx, gameState);
+        }
+
+        // Restore context
+        ctx.restore();
+
+        // Render UI (no camera translation)
+        this.renderUI(ctx, gameState, config);
+    }
+
+    /**
+     * Render background with sky gradient and clouds
+     */
+    renderBackground(ctx, camera, config) {
+        // Sky gradient
+        const gradient = ctx.createLinearGradient(0, 0, 0, config.canvasHeight);
+        gradient.addColorStop(0, '#87CEEB');
+        gradient.addColorStop(1, '#98FB98');
+        ctx.fillStyle = gradient;
+        ctx.fillRect(0, 0, config.canvasWidth, config.canvasHeight);
+
+        // Clouds (parallax scrolling - slower than camera)
+        ctx.fillStyle = 'rgba(255, 255, 255, 0.8)';
+        for (let i = 0; i < 5; i++) {
+            const x = (i * 300 + 100 - camera.x * 0.3) % (config.canvasWidth + 200);
+            const y = 80 + i * 30;
+            this.renderCloud(ctx, x, y);
+        }
+    }
+
+    /**
+     * Render a single cloud
+     */
+    renderCloud(ctx, x, y) {
+        ctx.beginPath();
+        ctx.arc(x, y, 30, 0, Math.PI * 2);
+        ctx.arc(x + 30, y, 40, 0, Math.PI * 2);
+        ctx.arc(x + 60, y, 30, 0, Math.PI * 2);
+        ctx.fill();
+    }
+
+    /**
+     * Render platforms
+     */
+    renderPlatforms(ctx, platforms) {
+        platforms.forEach(platform => {
+            ctx.fillStyle = platform.color;
+            ctx.fillRect(platform.x, platform.y, platform.width, platform.height);
+
+            // Add outline
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 2;
+            ctx.strokeRect(platform.x, platform.y, platform.width, platform.height);
+        });
+    }
+
+    /**
+     * Render question blocks
+     */
+    renderQuestionBlocks(ctx, questionBlocks) {
+        questionBlocks.forEach(block => {
+            // Block body
+            ctx.fillStyle = block.hit ? '#666' : '#FFD700';
+            ctx.fillRect(block.x, block.y, block.width, block.height);
+
+            // Border
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 2;
+            ctx.strokeRect(block.x, block.y, block.width, block.height);
+
+            // Question mark (if not hit)
+            if (!block.hit) {
+                ctx.fillStyle = '#000';
+                ctx.font = 'bold 24px Arial';
+                ctx.textAlign = 'center';
+                ctx.textBaseline = 'middle';
+                ctx.fillText('?', block.x + block.width / 2, block.y + block.height / 2);
+            }
+        });
+    }
+
+    /**
+     * Render enemies
+     */
+    renderEnemies(ctx, enemies) {
+        enemies.forEach(enemy => {
+            // Enemy body
+            ctx.fillStyle = '#FF6B6B';
+            ctx.fillRect(enemy.x, enemy.y, enemy.width, enemy.height);
+
+            // Eyes
+            ctx.fillStyle = '#FFF';
+            ctx.fillRect(enemy.x + 5, enemy.y + 5, 8, 8);
+            ctx.fillRect(enemy.x + enemy.width - 13, enemy.y + 5, 8, 8);
+
+            // Pupils
+            ctx.fillStyle = '#000';
+            ctx.fillRect(enemy.x + 7, enemy.y + 7, 4, 4);
+            ctx.fillRect(enemy.x + enemy.width - 11, enemy.y + 7, 4, 4);
+
+            // Border
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 2;
+            ctx.strokeRect(enemy.x, enemy.y, enemy.width, enemy.height);
+        });
+    }
+
+    /**
+     * Render walls
+     */
+    renderWalls(ctx, walls) {
+        walls.forEach(wall => {
+            // Main wall color
+            ctx.fillStyle = wall.color || '#8B4513';
+            ctx.fillRect(wall.x, wall.y, wall.width, wall.height);
+
+            // Brick pattern
+            ctx.strokeStyle = '#654321';
+            ctx.lineWidth = 2;
+
+            const brickWidth = 40;
+            const brickHeight = 20;
+
+            for (let y = wall.y; y < wall.y + wall.height; y += brickHeight) {
+                const offset = Math.floor((y - wall.y) / brickHeight) % 2 === 0 ? 0 : brickWidth / 2;
+                for (let x = wall.x + offset; x < wall.x + wall.width; x += brickWidth) {
+                    ctx.strokeRect(x, y, Math.min(brickWidth, wall.x + wall.width - x), brickHeight);
+                }
+            }
+
+            // Outer border
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 3;
+            ctx.strokeRect(wall.x, wall.y, wall.width, wall.height);
+        });
+    }
+
+    /**
+     * Render piranha plants
+     */
+    renderPiranhaPlants(ctx, plants) {
+        plants.forEach(plant => {
+            if (!plant.visible) return;
+
+            const pipeHeight = 60;
+            const pipeY = plant.y + plant.height - pipeHeight;
+
+            // Pipe
+            ctx.fillStyle = '#2D882D';
+            ctx.fillRect(plant.x, pipeY, plant.width, pipeHeight);
+
+            // Pipe rim
+            ctx.fillStyle = '#3A9F3A';
+            ctx.fillRect(plant.x - 5, pipeY, plant.width + 10, 10);
+
+            // Pipe border
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 2;
+            ctx.strokeRect(plant.x, pipeY, plant.width, pipeHeight);
+            ctx.strokeRect(plant.x - 5, pipeY, plant.width + 10, 10);
+
+            // Plant head (if extended)
+            if (plant.extended > 0) {
+                const headY = pipeY - plant.extended;
+                const headSize = 30;
+
+                // Head
+                ctx.fillStyle = '#FF0000';
+                ctx.beginPath();
+                ctx.arc(plant.x + plant.width / 2, headY, headSize, 0, Math.PI * 2);
+                ctx.fill();
+                ctx.stroke();
+
+                // Spots
+                ctx.fillStyle = '#FFF';
+                ctx.beginPath();
+                ctx.arc(plant.x + plant.width / 2 - 10, headY - 5, 6, 0, Math.PI * 2);
+                ctx.arc(plant.x + plant.width / 2 + 10, headY - 5, 6, 0, Math.PI * 2);
+                ctx.fill();
+
+                // Mouth (open/close animation)
+                const mouthOpen = Math.sin(Date.now() / 200) > 0;
+                if (mouthOpen) {
+                    ctx.fillStyle = '#000';
+                    ctx.fillRect(plant.x + plant.width / 2 - 12, headY + 8, 24, 8);
+                }
+
+                // Stem
+                ctx.fillStyle = '#2D882D';
+                ctx.fillRect(plant.x + plant.width / 2 - 5, headY, 10, plant.extended);
+            }
+        });
+    }
+
+    /**
+     * Render projectiles
+     */
+    renderProjectiles(ctx, projectiles) {
+        projectiles.forEach(proj => {
+            ctx.fillStyle = proj.color || '#FF4444';
+            ctx.beginPath();
+            ctx.arc(proj.x, proj.y, proj.radius, 0, Math.PI * 2);
+            ctx.fill();
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 2;
+            ctx.stroke();
+        });
+    }
+
+    /**
+     * Render catapults
+     */
+    renderCatapults(ctx, catapults) {
+        catapults.forEach(catapult => {
+            // Base
+            ctx.fillStyle = '#654321';
+            ctx.fillRect(catapult.x, catapult.y + 20, catapult.width, 20);
+
+            // Arm
+            ctx.save();
+            ctx.translate(catapult.x + catapult.width / 2, catapult.y + 30);
+            ctx.rotate(catapult.armAngle);
+            ctx.fillStyle = '#8B4513';
+            ctx.fillRect(-5, -40, 10, 40);
+            ctx.restore();
+
+            // Border
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 2;
+            ctx.strokeRect(catapult.x, catapult.y + 20, catapult.width, 20);
+        });
+    }
+
+    /**
+     * Render boulders
+     */
+    renderBoulders(ctx, boulders) {
+        boulders.forEach(boulder => {
+            // Boulder body
+            ctx.fillStyle = '#808080';
+            ctx.beginPath();
+            ctx.arc(boulder.x, boulder.y, boulder.radius, 0, Math.PI * 2);
+            ctx.fill();
+
+            // Cracks/texture
+            ctx.strokeStyle = '#606060';
+            ctx.lineWidth = 2;
+            ctx.beginPath();
+            ctx.moveTo(boulder.x - boulder.radius * 0.5, boulder.y - boulder.radius * 0.3);
+            ctx.lineTo(boulder.x + boulder.radius * 0.5, boulder.y + boulder.radius * 0.3);
+            ctx.stroke();
+
+            // Border
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 2;
+            ctx.beginPath();
+            ctx.arc(boulder.x, boulder.y, boulder.radius, 0, Math.PI * 2);
+            ctx.stroke();
+        });
+    }
+
+    /**
+     * Render stones (stone rain)
+     */
+    renderStones(ctx, stones) {
+        stones.forEach(stone => {
+            ctx.fillStyle = '#A9A9A9';
+            ctx.fillRect(stone.x, stone.y, stone.width, stone.height);
+
+            ctx.strokeStyle = '#000';
+            ctx.lineWidth = 1;
+            ctx.strokeRect(stone.x, stone.y, stone.width, stone.height);
+        });
+    }
+
+    /**
+     * Render flying eyes
+     */
+    renderFlyingEyes(ctx, eyes) {
+        eyes.forEach(eye => {
+            // Outer eye shape
+            ctx.fillStyle = '#FFE6E6';
+            ctx.beginPath();
+            ctx.ellipse(eye.x, eye.y, eye.width / 2, eye.height / 2, 0, 0, Math.PI * 2);
+            ctx.fill();
+            ctx.strokeStyle = '#FF0000';
+            ctx.lineWidth = 2;
+            ctx.stroke();
+
+            // Iris
+            ctx.fillStyle = '#8B0000';
+            ctx.beginPath();
+            ctx.arc(eye.x, eye.y, eye.width / 4, 0, Math.PI * 2);
+            ctx.fill();
+
+            // Pupil
+            ctx.fillStyle = '#000';
+            ctx.beginPath();
+            ctx.arc(eye.x, eye.y, eye.width / 8, 0, Math.PI * 2);
+            ctx.fill();
+
+            // Health bar
+            if (eye.health < eye.maxHealth) {
+                const barWidth = eye.width;
+                const barHeight = 4;
+                const barX = eye.x - barWidth / 2;
+                const barY = eye.y - eye.height / 2 - 10;
+
+                // Background
+                ctx.fillStyle = '#FF0000';
+                ctx.fillRect(barX, barY, barWidth, barHeight);
+
+                // Health
+                ctx.fillStyle = '#00FF00';
+                const healthWidth = (eye.health / eye.maxHealth) * barWidth;
+                ctx.fillRect(barX, barY, healthWidth, barHeight);
+
+                // Border
+                ctx.strokeStyle = '#000';
+                ctx.lineWidth = 1;
+                ctx.strokeRect(barX, barY, barWidth, barHeight);
+            }
+        });
+    }
+
+    /**
+     * Render boss
+     */
+    renderBoss(ctx, boss) {
+        if (!boss || !boss.active) return;
+
+        // Boss body (large imposing figure)
+        ctx.fillStyle = boss.enraged ? '#8B0000' : '#FF4444';
+        ctx.fillRect(boss.x, boss.y, boss.width, boss.height);
+
+        // Armor plates
+        ctx.fillStyle = '#2F4F4F';
+        ctx.fillRect(boss.x + 10, boss.y + 20, boss.width - 20, 20);
+        ctx.fillRect(boss.x + 10, boss.y + 60, boss.width - 20, 20);
+
+        // Eyes (angry)
+        ctx.fillStyle = boss.enraged ? '#FFFF00' : '#FFF';
+        ctx.fillRect(boss.x + 20, boss.y + 40, 30, 20);
+        ctx.fillRect(boss.x + boss.width - 50, boss.y + 40, 30, 20);
+
+        // Pupils (follow player)
+        ctx.fillStyle = '#000';
+        ctx.fillRect(boss.x + 35, boss.y + 45, 10, 10);
+        ctx.fillRect(boss.x + boss.width - 35, boss.y + 45, 10, 10);
+
+        // Boss border
+        ctx.strokeStyle = '#000';
+        ctx.lineWidth = 4;
+        ctx.strokeRect(boss.x, boss.y, boss.width, boss.height);
+
+        // Health bar (prominent)
+        const barWidth = boss.width;
+        const barHeight = 10;
+        const barX = boss.x;
+        const barY = boss.y - 20;
+
+        // Background
+        ctx.fillStyle = '#400000';
+        ctx.fillRect(barX, barY, barWidth, barHeight);
+
+        // Health
+        const healthPercent = boss.health / boss.maxHealth;
+        ctx.fillStyle = healthPercent > 0.5 ? '#00FF00' : healthPercent > 0.25 ? '#FFFF00' : '#FF0000';
+        ctx.fillRect(barX, barY, barWidth * healthPercent, barHeight);
+
+        // Border
+        ctx.strokeStyle = '#000';
+        ctx.lineWidth = 2;
+        ctx.strokeRect(barX, barY, barWidth, barHeight);
+
+        // Boss name/title
+        ctx.fillStyle = '#FFF';
+        ctx.strokeStyle = '#000';
+        ctx.lineWidth = 3;
+        ctx.font = 'bold 16px Arial';
+        ctx.textAlign = 'center';
+        ctx.strokeText('COLOSSAL BOSS', boss.x + boss.width / 2, barY - 5);
+        ctx.fillText('COLOSSAL BOSS', boss.x + boss.width / 2, barY - 5);
+    }
+
+    /**
+     * Render castle
+     */
+    renderCastle(ctx, castle) {
+        if (!castle) return;
+
+        // Main castle body
+        ctx.fillStyle = '#888';
+        ctx.fillRect(castle.x, castle.y, castle.width, castle.height);
+
+        // Towers
+        const towerWidth = 40;
+        const towerHeight = 80;
+
+        // Left tower
+        ctx.fillRect(castle.x - 20, castle.y - 30, towerWidth, towerHeight);
+
+        // Right tower
+        ctx.fillRect(castle.x + castle.width - 20, castle.y - 30, towerWidth, towerHeight);
+
+        // Tower tops (triangular)
+        ctx.fillStyle = '#666';
+        ctx.beginPath();
+        ctx.moveTo(castle.x - 20, castle.y - 30);
+        ctx.lineTo(castle.x + 20, castle.y - 60);
+        ctx.lineTo(castle.x + 20, castle.y - 30);
+        ctx.fill();
+
+        ctx.beginPath();
+        ctx.moveTo(castle.x + castle.width - 20, castle.y - 30);
+        ctx.lineTo(castle.x + castle.width + 20, castle.y - 60);
+        ctx.lineTo(castle.x + castle.width + 20, castle.y - 30);
+        ctx.fill();
+
+        // Door
+        ctx.fillStyle = '#654321';
+        ctx.fillRect(castle.x + castle.width / 2 - 20, castle.y + castle.height - 50, 40, 50);
+
+        // Windows
+        ctx.fillStyle = '#FFFF00';
+        ctx.fillRect(castle.x + 20, castle.y + 20, 15, 20);
+        ctx.fillRect(castle.x + castle.width - 35, castle.y + 20, 15, 20);
+
+        // Borders
+        ctx.strokeStyle = '#000';
+        ctx.lineWidth = 2;
+        ctx.strokeRect(castle.x, castle.y, castle.width, castle.height);
+    }
+
+    /**
+     * Render finish line
+     */
+    renderFinishLine(ctx, finishLine, currentLevel) {
+        // Checkered flag pole
+        ctx.fillStyle = '#000';
+        ctx.fillRect(finishLine.x, finishLine.y, 5, finishLine.height);
+
+        // Flag (checkered pattern)
+        const flagWidth = 60;
+        const flagHeight = 40;
+        const squareSize = 10;
+
+        for (let y = 0; y < flagHeight; y += squareSize) {
+            for (let x = 0; x < flagWidth; x += squareSize) {
+                const isBlack = ((x / squareSize) + (y / squareSize)) % 2 === 0;
+                ctx.fillStyle = isBlack ? '#000' : '#FFF';
+                ctx.fillRect(finishLine.x + 5 + x, finishLine.y + y, squareSize, squareSize);
+            }
+        }
+
+        // Flag border
+        ctx.strokeStyle = '#000';
+        ctx.lineWidth = 2;
+        ctx.strokeRect(finishLine.x + 5, finishLine.y, flagWidth, flagHeight);
+
+        // Level number on flag
+        ctx.fillStyle = '#FFD700';
+        ctx.strokeStyle = '#000';
+        ctx.lineWidth = 2;
+        ctx.font = 'bold 16px Arial';
+        ctx.textAlign = 'center';
+        ctx.strokeText(`${currentLevel + 1}`, finishLine.x + 35, finishLine.y + 25);
+        ctx.fillText(`${currentLevel + 1}`, finishLine.x + 35, finishLine.y + 25);
+    }
+
+    /**
+     * Render Mario
+     */
+    renderMario(ctx, mario) {
+        // Mario body
+        ctx.fillStyle = '#FF0000';
+        ctx.fillRect(mario.x, mario.y, mario.width, mario.height);
+
+        // Overalls
+        ctx.fillStyle = '#0000FF';
+        ctx.fillRect(mario.x + 5, mario.y + mario.height / 2, mario.width - 10, mario.height / 2);
+
+        // Face
+        ctx.fillStyle = '#FFD700';
+        ctx.fillRect(mario.x + 8, mario.y + 5, mario.width - 16, 15);
+
+        // Eyes
+        ctx.fillStyle = '#000';
+        ctx.fillRect(mario.x + 10, mario.y + 10, 4, 4);
+        ctx.fillRect(mario.x + mario.width - 14, mario.y + 10, 4, 4);
+
+        // Border
+        ctx.strokeStyle = '#000';
+        ctx.lineWidth = 2;
+        ctx.strokeRect(mario.x, mario.y, mario.width, mario.height);
+    }
+
+    /**
+     * Render particles (explosions, dust, etc.)
+     */
+    renderParticles(ctx, particles) {
+        particles.forEach(particle => {
+            ctx.fillStyle = particle.color;
+            ctx.globalAlpha = particle.life;
+            ctx.fillRect(particle.x - 2, particle.y - 2, 4, 4);
+        });
+        ctx.globalAlpha = 1.0; // Reset alpha
+    }
+
+    /**
+     * Render UI overlay (lives, score, level)
+     */
+    renderUI(ctx, gameState, config) {
+        // Semi-transparent background
+        ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
+        ctx.fillRect(0, 0, config.canvasWidth, 40);
+
+        // Text style
+        ctx.fillStyle = '#FFF';
+        ctx.font = 'bold 16px Arial';
+        ctx.textAlign = 'left';
+
+        // Lives
+        ctx.fillText(`❤️ Lives: ${gameState.lives}`, 10, 25);
+
+        // Score
+        ctx.textAlign = 'center';
+        ctx.fillText(`Score: ${gameState.score}`, config.canvasWidth / 2, 25);
+
+        // Level
+        ctx.textAlign = 'right';
+        ctx.fillText(`Level: ${gameState.currentLevel + 1}`, config.canvasWidth - 10, 25);
+    }
+
+    /**
+     * Render debug hitboxes (for development)
+     */
+    renderDebugHitboxes(ctx, gameState) {
+        ctx.strokeStyle = '#FF00FF';
+        ctx.lineWidth = 1;
+
+        // Mario hitbox
+        ctx.strokeRect(gameState.mario.x, gameState.mario.y, gameState.mario.width, gameState.mario.height);
+
+        // Enemy hitboxes
+        if (gameState.enemies) {
+            gameState.enemies.forEach(enemy => {
+                ctx.strokeRect(enemy.x, enemy.y, enemy.width, enemy.height);
+            });
+        }
+
+        // Platform hitboxes
+        if (gameState.platforms) {
+            gameState.platforms.forEach(platform => {
+                ctx.strokeRect(platform.x, platform.y, platform.width, platform.height);
+            });
+        }
+    }
+}
+
+// Export singleton instance
+export const renderer = new Renderer();
diff --git a/src/gameHelpers/MarioEducational/SentenceGenerator.js b/src/gameHelpers/MarioEducational/SentenceGenerator.js
new file mode 100644
index 0000000..488ac04
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/SentenceGenerator.js
@@ -0,0 +1,386 @@
+/**
+ * SentenceGenerator.js
+ * Helper for generating contextual educational sentences from vocabulary words
+ * Handles proper grammar, articles, verb conjugation, and context variety
+ */
+
+export class SentenceGenerator {
+    constructor() {
+        // Vowel sounds for article detection
+        this._vowelSounds = ['a', 'e', 'i', 'o', 'u'];
+
+        // Special cases for articles (words starting with 'u' that use 'a')
+        this._aExceptions = ['university', 'uniform', 'unicorn', 'unique', 'unit', 'union'];
+
+        // Common irregular verbs (present tense 3rd person)
+        this._irregularVerbs = {
+            'go': 'goes',
+            'do': 'does',
+            'have': 'has',
+            'be': 'is',
+            'say': 'says',
+            'try': 'tries',
+            'fly': 'flies',
+            'cry': 'cries',
+            'study': 'studies'
+        };
+
+        // Sentence templates by word type with proper grammar
+        this._templates = {
+            'noun': {
+                beginner: [
+                    (w) => `This is ${this._getArticle(w)} ${w}.`,
+                    (w) => `I see ${this._getArticle(w)} ${w}.`,
+                    (w) => `Look at the ${w}!`,
+                    (w) => `I have ${this._getArticle(w)} ${w}.`,
+                    (w) => `Where is the ${w}?`
+                ],
+                intermediate: [
+                    (w) => `The ${w} is on the table.`,
+                    (w) => `I need ${this._getArticle(w)} ${w} for this task.`,
+                    (w) => `Can you find the ${w}?`,
+                    (w) => `She bought ${this._getArticle(w)} ${w} yesterday.`,
+                    (w) => `The ${w} looks beautiful today.`
+                ],
+                advanced: [
+                    (w) => `The ${w} represents an important concept in our discussion.`,
+                    (w) => `Without ${this._getArticle(w)} ${w}, this would be impossible.`,
+                    (w) => `The ${w} has become increasingly popular recently.`,
+                    (w) => `Many people underestimate the value of ${this._getArticle(w)} ${w}.`,
+                    (w) => `The ${w} plays a crucial role in this process.`
+                ]
+            },
+            'verb': {
+                beginner: [
+                    (w) => `I ${w} every day.`,
+                    (w) => `Please ${w} this.`,
+                    (w) => `Can you ${w}?`,
+                    (w) => `Let's ${w} together.`,
+                    (w) => `Don't ${w} too fast.`
+                ],
+                intermediate: [
+                    (w) => `She ${this._conjugateThirdPerson(w)} every morning.`,
+                    (w) => `They will ${w} tomorrow.`,
+                    (w) => `We should ${w} more often.`,
+                    (w) => `He ${this._conjugateThirdPerson(w)} very well.`,
+                    (w) => `I want to ${w} better.`
+                ],
+                advanced: [
+                    (w) => `The ability to ${w} effectively is essential.`,
+                    (w) => `She has been ${this._getGerund(w)} for years.`,
+                    (w) => `Learning to ${w} requires practice and patience.`,
+                    (w) => `He ${this._conjugateThirdPerson(w)} with remarkable skill.`,
+                    (w) => `They decided to ${w} despite the challenges.`
+                ]
+            },
+            'adjective': {
+                beginner: [
+                    (w) => `It is ${w}.`,
+                    (w) => `The house is ${w}.`,
+                    (w) => `This looks ${w}.`,
+                    (w) => `How ${w}!`,
+                    (w) => `Very ${w} indeed.`
+                ],
+                intermediate: [
+                    (w) => `The weather seems quite ${w} today.`,
+                    (w) => `She appears ${w} and happy.`,
+                    (w) => `This is more ${w} than before.`,
+                    (w) => `The ${w} building stands tall.`,
+                    (w) => `Everyone feels ${w} about it.`
+                ],
+                advanced: [
+                    (w) => `The ${w} atmosphere created a perfect ambiance.`,
+                    (w) => `His ${w} demeanor impressed everyone.`,
+                    (w) => `The situation became increasingly ${w}.`,
+                    (w) => `She maintained a ${w} attitude throughout.`,
+                    (w) => `The ${w} nature of the problem requires attention.`
+                ]
+            },
+            'adverb': {
+                beginner: [
+                    (w) => `Walk ${w}.`,
+                    (w) => `Do it ${w}.`,
+                    (w) => `Move ${w}.`,
+                    (w) => `Talk ${w}.`,
+                    (w) => `Run ${w}.`
+                ],
+                intermediate: [
+                    (w) => `He speaks ${w} and clearly.`,
+                    (w) => `She works ${w} every day.`,
+                    (w) => `They arrived ${w} at the meeting.`,
+                    (w) => `The car moves ${w} down the road.`,
+                    (w) => `Please listen ${w} to the instructions.`
+                ],
+                advanced: [
+                    (w) => `The team performed ${w} under pressure.`,
+                    (w) => `She ${w} explained the complex concept.`,
+                    (w) => `The project progressed ${w} despite setbacks.`,
+                    (w) => `He ${w} adapted to the new environment.`,
+                    (w) => `The strategy was ${w} implemented.`
+                ]
+            },
+            'preposition': {
+                beginner: [
+                    (w) => `The book is ${w} the table.`,
+                    (w) => `Go ${w} the door.`,
+                    (w) => `Look ${w} the window.`,
+                    (w) => `It's ${w} the box.`,
+                    (w) => `Put it ${w} here.`
+                ],
+                intermediate: [
+                    (w) => `The cat jumped ${w} the fence.`,
+                    (w) => `We walked ${w} the park together.`,
+                    (w) => `She placed it ${w} the shelf.`,
+                    (w) => `They traveled ${w} the mountains.`,
+                    (w) => `The bird flew ${w} the trees.`
+                ],
+                advanced: [
+                    (w) => `The discussion centered ${w} the main topic.`,
+                    (w) => `Success depends ${w} consistent effort.`,
+                    (w) => `The solution lies ${w} these principles.`,
+                    (w) => `Progress moved ${w} expectations.`,
+                    (w) => `The argument stands ${w} scrutiny.`
+                ]
+            }
+        };
+    }
+
+    /**
+     * Get appropriate article (a/an) for a word
+     * @param {string} word - The word to check
+     * @returns {string} - "a" or "an"
+     */
+    _getArticle(word) {
+        if (!word) return 'a';
+
+        const firstLetter = word.charAt(0).toLowerCase();
+
+        // Check exceptions (words starting with 'u' but pronounced with consonant sound)
+        if (this._aExceptions.some(exception => word.toLowerCase().startsWith(exception))) {
+            return 'a';
+        }
+
+        // Check if starts with vowel sound
+        return this._vowelSounds.includes(firstLetter) ? 'an' : 'a';
+    }
+
+    /**
+     * Conjugate verb to 3rd person singular present
+     * @param {string} verb - Base form of verb
+     * @returns {string} - Conjugated verb
+     */
+    _conjugateThirdPerson(verb) {
+        if (!verb) return verb;
+
+        // Check irregular verbs
+        if (this._irregularVerbs[verb.toLowerCase()]) {
+            return this._irregularVerbs[verb.toLowerCase()];
+        }
+
+        // Regular conjugation rules
+        const lowerVerb = verb.toLowerCase();
+
+        // Verbs ending in -y preceded by consonant: try -> tries
+        if (lowerVerb.endsWith('y') && lowerVerb.length > 1) {
+            const beforeY = lowerVerb.charAt(lowerVerb.length - 2);
+            if (!'aeiou'.includes(beforeY)) {
+                return verb.slice(0, -1) + 'ies';
+            }
+        }
+
+        // Verbs ending in -s, -x, -z, -ch, -sh: add -es
+        if (lowerVerb.endsWith('s') || lowerVerb.endsWith('x') ||
+            lowerVerb.endsWith('z') || lowerVerb.endsWith('ch') ||
+            lowerVerb.endsWith('sh')) {
+            return verb + 'es';
+        }
+
+        // Verbs ending in -o: add -es
+        if (lowerVerb.endsWith('o')) {
+            return verb + 'es';
+        }
+
+        // Default: add -s
+        return verb + 's';
+    }
+
+    /**
+     * Convert verb to gerund form (present participle)
+     * @param {string} verb - Base form of verb
+     * @returns {string} - Gerund form
+     */
+    _getGerund(verb) {
+        if (!verb) return verb;
+
+        const lowerVerb = verb.toLowerCase();
+
+        // Verbs ending in -e: remove -e and add -ing (make -> making)
+        if (lowerVerb.endsWith('e') && lowerVerb !== 'be') {
+            return verb.slice(0, -1) + 'ing';
+        }
+
+        // Verbs ending in -ie: change to -ying (lie -> lying)
+        if (lowerVerb.endsWith('ie')) {
+            return verb.slice(0, -2) + 'ying';
+        }
+
+        // Single syllable verbs ending in consonant-vowel-consonant: double last letter
+        // (run -> running, stop -> stopping)
+        if (lowerVerb.length >= 3) {
+            const last = lowerVerb.slice(-1);
+            const secondLast = lowerVerb.slice(-2, -1);
+            const thirdLast = lowerVerb.slice(-3, -2);
+
+            const isConsonant = (c) => !'aeiou'.includes(c);
+
+            if (isConsonant(last) && !isConsonant(secondLast) && isConsonant(thirdLast)) {
+                // But not for verbs ending in w, x, y
+                if (!'wxy'.includes(last)) {
+                    return verb + last + 'ing';
+                }
+            }
+        }
+
+        // Default: add -ing
+        return verb + 'ing';
+    }
+
+    /**
+     * Determine difficulty level from word frequency or context
+     * @param {Object} data - Word data
+     * @returns {string} - "beginner", "intermediate", or "advanced"
+     */
+    _getDifficultyLevel(data) {
+        // You can enhance this with actual word frequency data or CEFR levels
+        // For now, use simple heuristics
+
+        if (data.level) {
+            return data.level; // If explicitly provided
+        }
+
+        // Simple heuristic: word length
+        const wordLength = (data.word || '').length;
+        if (wordLength <= 5) return 'beginner';
+        if (wordLength <= 8) return 'intermediate';
+        return 'advanced';
+    }
+
+    /**
+     * Generate a contextual sentence from a vocabulary word
+     * @param {string} word - The vocabulary word
+     * @param {Object} data - Word data including type and translation
+     * @returns {Object} - Generated sentence with English and translation
+     */
+    generateSentence(word, data) {
+        if (!word || !data) {
+            console.warn('Invalid word or data for sentence generation');
+            return {
+                english: `This is ${word}.`,
+                translation: `${data?.user_language || word}`
+            };
+        }
+
+        const type = (data.type || 'noun').toLowerCase();
+        const translation = data.user_language ? data.user_language.split('；')[0].trim() : word;
+        const difficulty = this._getDifficultyLevel({...data, word});
+
+        // Get templates for this type and difficulty
+        const typeTemplates = this._templates[type] || this._templates['noun'];
+        const difficultyTemplates = typeTemplates[difficulty] || typeTemplates['beginner'];
+
+        // Select random template
+        const randomTemplate = difficultyTemplates[Math.floor(Math.random() * difficultyTemplates.length)];
+
+        // Generate sentence using template function
+        const englishSentence = randomTemplate(word);
+
+        // Create translation with highlighted word
+        const highlightedWord = `**${word}**`;
+        const translationText = `${translation} - ${englishSentence.replace(new RegExp(`\\b${word}\\b`, 'gi'), highlightedWord)}`;
+
+        return {
+            english: englishSentence,
+            translation: translationText,
+            difficulty: difficulty,
+            wordType: type
+        };
+    }
+
+    /**
+     * Split long text into individual sentences
+     * @param {string} text - Long text to split
+     * @returns {Array} - Array of sentences
+     */
+    splitTextIntoSentences(text) {
+        if (!text || typeof text !== 'string') return [];
+
+        // Clean the text
+        text = text.trim();
+
+        // Split by common sentence endings (., !, ?)
+        // But preserve abbreviations like "Mr.", "Dr.", etc.
+        const sentences = text.split(/(?<=[.!?])\s+(?=[A-Z])/);
+
+        return sentences
+            .map(s => s.trim())
+            .filter(s => s.length > 0 && s.length < 200) // Filter out too long or empty
+            .filter(s => {
+                // Filter out sentences that are just numbers or too short
+                const words = s.split(/\s+/);
+                return words.length >= 3 && words.length <= 30;
+            });
+    }
+
+    /**
+     * Validate generated sentence quality
+     * @param {Object} sentence - Generated sentence object
+     * @returns {boolean} - True if sentence meets quality standards
+     */
+    isValidSentence(sentence) {
+        if (!sentence || !sentence.english) return false;
+
+        const words = sentence.english.split(/\s+/);
+
+        // Must have at least 2 words
+        if (words.length < 2) return false;
+
+        // Must end with proper punctuation
+        if (!/[.!?]$/.test(sentence.english)) return false;
+
+        // Must start with capital letter
+        if (!/^[A-Z]/.test(sentence.english)) return false;
+
+        return true;
+    }
+
+    /**
+     * Generate multiple sentences from a word list
+     * @param {Array} wordList - Array of {word, data} objects
+     * @param {number} count - Number of sentences to generate
+     * @returns {Array} - Array of sentence objects
+     */
+    generateMultipleSentences(wordList, count = 10) {
+        const sentences = [];
+
+        for (let i = 0; i < Math.min(count, wordList.length); i++) {
+            const {word, data} = wordList[i];
+            const sentence = this.generateSentence(word, data);
+
+            if (this.isValidSentence(sentence)) {
+                sentences.push({
+                    type: 'vocabulary',
+                    english: sentence.english,
+                    translation: sentence.translation,
+                    context: data.type || 'vocabulary',
+                    difficulty: sentence.difficulty,
+                    wordType: sentence.wordType
+                });
+            }
+        }
+
+        return sentences;
+    }
+}
+
+// Export singleton instance
+export const sentenceGenerator = new SentenceGenerator();
diff --git a/src/gameHelpers/MarioEducational/SoundSystem.js b/src/gameHelpers/MarioEducational/SoundSystem.js
new file mode 100644
index 0000000..2e72304
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/SoundSystem.js
@@ -0,0 +1,272 @@
+/**
+ * SoundSystem.js
+ * Helper for managing Web Audio API sound generation and playback
+ * Generates programmatic retro game sounds without external audio files
+ */
+
+export class SoundSystem {
+    constructor() {
+        this._audioContext = null;
+        this._sounds = {};
+        this._initialized = false;
+    }
+
+    /**
+     * Initialize the Web Audio Context
+     * @returns {boolean} - True if initialization successful
+     */
+    initialize() {
+        if (this._initialized) {
+            console.log('🔊 Sound system already initialized');
+            return true;
+        }
+
+        try {
+            // Initialize Web Audio Context
+            this._audioContext = new (window.AudioContext || window.webkitAudioContext)();
+            console.log('🔊 Sound system initialized');
+
+            // Create sound library
+            this._createSoundLibrary();
+            this._initialized = true;
+            return true;
+        } catch (error) {
+            console.warn('⚠️ Sound system not available:', error);
+            this._audioContext = null;
+            this._initialized = false;
+            return false;
+        }
+    }
+
+    /**
+     * Create the library of available sounds
+     * Each sound is defined with parameters for programmatic generation
+     */
+    _createSoundLibrary() {
+        // Sound definitions with parameters for programmatic generation
+        this._sounds = {
+            jump: {
+                type: 'sweep',
+                frequency: 330,
+                endFrequency: 600,
+                duration: 0.1
+            },
+            coin: {
+                type: 'bell',
+                frequency: 800,
+                duration: 0.3
+            },
+            powerup: {
+                type: 'arpeggio',
+                frequencies: [264, 330, 396, 528],
+                duration: 0.6
+            },
+            enemy_defeat: {
+                type: 'noise_sweep',
+                frequency: 200,
+                endFrequency: 50,
+                duration: 0.2
+            },
+            question_block: {
+                type: 'sparkle',
+                frequency: 600,
+                endFrequency: 1200,
+                duration: 0.4
+            },
+            level_complete: {
+                type: 'victory',
+                frequencies: [523, 659, 784, 1047],
+                duration: 1.0
+            },
+            death: {
+                type: 'descend',
+                frequency: 300,
+                endFrequency: 100,
+                duration: 0.8
+            },
+            finish_stars: {
+                type: 'magical',
+                frequencies: [880, 1100, 1320, 1760],
+                duration: 2.0
+            }
+        };
+
+        console.log('🎵 Sound library created with', Object.keys(this._sounds).length, 'sounds');
+    }
+
+    /**
+     * Play a sound by name
+     * @param {string} soundName - Name of the sound to play
+     * @param {number} volume - Volume level (0.0 to 1.0)
+     */
+    play(soundName, volume = 0.3) {
+        if (!this._initialized || !this._audioContext || !this._sounds[soundName]) {
+            if (!this._sounds[soundName] && this._initialized) {
+                console.warn(`⚠️ Sound not found: ${soundName}`);
+            }
+            return;
+        }
+
+        try {
+            const sound = this._sounds[soundName];
+            const oscillator = this._audioContext.createOscillator();
+            const gainNode = this._audioContext.createGain();
+
+            oscillator.connect(gainNode);
+            gainNode.connect(this._audioContext.destination);
+
+            const currentTime = this._audioContext.currentTime;
+            const duration = sound.duration;
+
+            // Set volume envelope (fade in/out)
+            gainNode.gain.setValueAtTime(0, currentTime);
+            gainNode.gain.linearRampToValueAtTime(volume, currentTime + 0.01);
+            gainNode.gain.exponentialRampToValueAtTime(0.01, currentTime + duration);
+
+            // Configure sound based on type
+            this._configureSoundType(oscillator, sound, currentTime, duration);
+
+            oscillator.start(currentTime);
+            oscillator.stop(currentTime + duration);
+
+            console.log(`🎵 Playing sound: ${soundName}`);
+
+        } catch (error) {
+            console.warn('⚠️ Failed to play sound:', soundName, error);
+        }
+    }
+
+    /**
+     * Configure oscillator based on sound type
+     * @param {OscillatorNode} oscillator - Web Audio oscillator
+     * @param {Object} sound - Sound configuration
+     * @param {number} currentTime - Current audio context time
+     * @param {number} duration - Sound duration
+     */
+    _configureSoundType(oscillator, sound, currentTime, duration) {
+        switch (sound.type) {
+            case 'sweep':
+                // Frequency sweep (jump sound)
+                oscillator.type = 'square';
+                oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
+                oscillator.frequency.linearRampToValueAtTime(sound.endFrequency, currentTime + duration);
+                break;
+
+            case 'bell':
+                // Bell-like sound (coin)
+                oscillator.type = 'sine';
+                oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
+                oscillator.frequency.exponentialRampToValueAtTime(sound.frequency * 0.5, currentTime + duration);
+                break;
+
+            case 'noise_sweep':
+                // Noise sweep (enemy defeat)
+                oscillator.type = 'sawtooth';
+                oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
+                oscillator.frequency.linearRampToValueAtTime(sound.endFrequency, currentTime + duration);
+                break;
+
+            case 'sparkle':
+                // Sparkle effect (question block)
+                oscillator.type = 'triangle';
+                oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
+                oscillator.frequency.linearRampToValueAtTime(sound.endFrequency, currentTime + duration * 0.7);
+                oscillator.frequency.linearRampToValueAtTime(sound.frequency, currentTime + duration);
+                break;
+
+            case 'descend':
+                // Descending tone (death)
+                oscillator.type = 'square';
+                oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
+                oscillator.frequency.exponentialRampToValueAtTime(sound.endFrequency, currentTime + duration);
+                break;
+
+            case 'arpeggio':
+            case 'victory':
+            case 'magical':
+                // Complex multi-note sounds
+                oscillator.type = sound.type === 'magical' ? 'triangle' : 'square';
+                oscillator.frequency.setValueAtTime(sound.frequencies[0], currentTime);
+
+                // Schedule frequency changes for arpeggio effect
+                const noteLength = duration / sound.frequencies.length;
+                sound.frequencies.forEach((freq, index) => {
+                    if (index > 0) {
+                        oscillator.frequency.setValueAtTime(freq, currentTime + noteLength * index);
+                    }
+                });
+                break;
+
+            default:
+                // Default fallback
+                oscillator.type = 'square';
+                oscillator.frequency.setValueAtTime(sound.frequency || 440, currentTime);
+        }
+    }
+
+    /**
+     * Add a custom sound to the library
+     * @param {string} name - Sound name
+     * @param {Object} config - Sound configuration
+     */
+    addSound(name, config) {
+        if (!name || !config) {
+            console.warn('⚠️ Invalid sound configuration');
+            return;
+        }
+
+        this._sounds[name] = config;
+        console.log(`🎵 Added custom sound: ${name}`);
+    }
+
+    /**
+     * Remove a sound from the library
+     * @param {string} name - Sound name to remove
+     */
+    removeSound(name) {
+        if (this._sounds[name]) {
+            delete this._sounds[name];
+            console.log(`🎵 Removed sound: ${name}`);
+        }
+    }
+
+    /**
+     * Get list of available sounds
+     * @returns {Array} - Array of sound names
+     */
+    getAvailableSounds() {
+        return Object.keys(this._sounds);
+    }
+
+    /**
+     * Check if sound system is initialized
+     * @returns {boolean}
+     */
+    isInitialized() {
+        return this._initialized;
+    }
+
+    /**
+     * Get the audio context (for advanced usage)
+     * @returns {AudioContext|null}
+     */
+    getAudioContext() {
+        return this._audioContext;
+    }
+
+    /**
+     * Cleanup and close audio context
+     */
+    destroy() {
+        if (this._audioContext) {
+            this._audioContext.close();
+            this._audioContext = null;
+        }
+        this._sounds = {};
+        this._initialized = false;
+        console.log('🔊 Sound system destroyed');
+    }
+}
+
+// Export singleton instance for convenience
+export const soundSystem = new SoundSystem();
diff --git a/src/gameHelpers/MarioEducational/enemies/Boss.js b/src/gameHelpers/MarioEducational/enemies/Boss.js
new file mode 100644
index 0000000..2fe13b6
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/enemies/Boss.js
@@ -0,0 +1,254 @@
+/**
+ * Boss.js
+ * Colossal Boss enemy for level 6
+ * Large immobile boss with turrets and special attacks
+ */
+
+export class Boss {
+    /**
+     * Generate the colossal boss for level 6
+     * @param {Object} level - Level data
+     * @param {number} levelWidth - Width of the level
+     * @param {number} canvasHeight - Canvas height
+     * @returns {Object} - Boss data with turrets
+     */
+    static generate(level, levelWidth, canvasHeight) {
+        console.log(`👹 Generating Colossal Boss for level 6!`);
+
+        // Boss positioned in center-right of level to block the path
+        const bossX = levelWidth * 0.6; // 60% through the level
+        const bossY = canvasHeight - 250; // Standing on ground
+        const bossWidth = 150;
+        const bossHeight = 200;
+
+        const boss = {
+            x: bossX,
+            y: bossY,
+            width: bossWidth,
+            height: bossHeight,
+            health: 5, // Takes 5 hits
+            maxHealth: 5,
+            color: '#2F4F4F', // Dark slate gray
+            type: 'colossus',
+            active: true,
+            // Collision boxes (knees for damage)
+            leftKnee: {
+                x: bossX + 20,
+                y: bossY + bossHeight - 60,
+                width: 40,
+                height: 40
+            },
+            rightKnee: {
+                x: bossX + bossWidth - 60,
+                y: bossY + bossHeight - 60,
+                width: 40,
+                height: 40
+            },
+            // Boss behavior
+            lastTurretShot: Date.now(),
+            turretCooldown: 2000, // Turrets fire every 2 seconds
+            lastMinionLaunch: Date.now(),
+            minionCooldown: 4000, // Launch minions every 4 seconds
+            // Visual
+            eyeColor: '#FF0000', // Red glowing eyes
+            isDamaged: false,
+            damageFlashTimer: 0,
+            enraged: false // Becomes enraged at low health
+        };
+
+        // Generate turrets on the boss (2 turrets)
+        const turrets = [
+            {
+                x: bossX + 30,
+                y: bossY + 50,
+                width: 25,
+                height: 25,
+                color: '#8B4513',
+                type: 'turret',
+                lastShot: Date.now(),
+                shootCooldown: 2500 // Individual cooldown
+            },
+            {
+                x: bossX + bossWidth - 55,
+                y: bossY + 50,
+                width: 25,
+                height: 25,
+                color: '#8B4513',
+                type: 'turret',
+                lastShot: Date.now(),
+                shootCooldown: 3000 // Slightly different timing
+            }
+        ];
+
+        console.log(`👹 Colossal Boss spawned at x=${bossX.toFixed(0)}, health=${boss.health}`);
+        console.log(`🔫 ${turrets.length} turrets mounted on boss`);
+
+        return { boss, turrets };
+    }
+
+    /**
+     * Update boss behavior
+     * @param {Object} boss - Boss object
+     * @param {Array} turrets - Boss turrets
+     * @param {Object} mario - Mario object
+     * @param {Array} projectiles - Projectiles array
+     * @param {Array} flyingEyes - Flying eyes array (for spawning minions)
+     * @param {Function} playSound - Sound callback
+     */
+    static update(boss, turrets, mario, projectiles, flyingEyes, playSound) {
+        if (!boss || !boss.active) return;
+
+        const currentTime = Date.now();
+
+        // Update boss state
+        if (boss.health < boss.maxHealth / 2) {
+            boss.enraged = true;
+        }
+
+        // Damage flash animation
+        if (boss.isDamaged) {
+            boss.damageFlashTimer--;
+            if (boss.damageFlashTimer <= 0) {
+                boss.isDamaged = false;
+            }
+        }
+
+        // Update turrets - they shoot projectiles at Mario
+        turrets.forEach(turret => {
+            if (currentTime - turret.lastShot > turret.shootCooldown) {
+                // Calculate trajectory to Mario
+                const dx = mario.x - turret.x;
+                const dy = mario.y - turret.y;
+                const distance = Math.sqrt(dx * dx + dy * dy);
+
+                const speed = boss.enraged ? 6 : 4; // Faster when enraged
+                const velocityX = (dx / distance) * speed;
+                const velocityY = (dy / distance) * speed;
+
+                projectiles.push({
+                    x: turret.x + turret.width / 2,
+                    y: turret.y + turret.height / 2,
+                    velocityX: velocityX,
+                    velocityY: velocityY,
+                    radius: 10,
+                    color: boss.enraged ? '#FF0000' : '#FF8C00', // Red when enraged, orange normally
+                    type: 'boss_projectile',
+                    life: 300
+                });
+
+                turret.lastShot = currentTime;
+                if (playSound) playSound('enemy_defeat');
+                console.log(`🔫 Boss turret fired at Mario!`);
+            }
+        });
+
+        // Spawn flying eye minions periodically
+        if (boss.enraged && currentTime - boss.lastMinionLaunch > boss.minionCooldown) {
+            // Spawn a flying eye minion
+            const minionX = boss.x + boss.width / 2;
+            const minionY = boss.y + 50;
+
+            flyingEyes.push({
+                x: minionX,
+                y: minionY,
+                width: 25,
+                height: 25,
+                velocityX: (Math.random() - 0.5) * 2,
+                velocityY: -3, // Fly upward initially
+                color: '#8B0000', // Dark red for minions
+                pupilColor: '#000000',
+                type: 'flying_eye_minion',
+                health: 1,
+                maxHealth: 1,
+                chaseDistance: 300,
+                chaseSpeed: 3,
+                idleSpeed: 1,
+                lastDirectionChange: Date.now(),
+                directionChangeInterval: 2000,
+                isChasing: false,
+                dashCooldown: 0,
+                dashDuration: 0,
+                isDashing: false,
+                dashSpeed: 6,
+                lastDashTime: Date.now(),
+                dashInterval: 4000,
+                blinkTimer: 0,
+                isBlinking: false
+            });
+
+            boss.lastMinionLaunch = currentTime;
+            if (playSound) playSound('powerup');
+            console.log(`👁️ Boss spawned a flying eye minion!`);
+        }
+    }
+
+    /**
+     * Damage the boss
+     * @param {Object} boss - Boss object
+     * @param {Function} playSound - Sound callback
+     * @returns {boolean} - True if boss was defeated
+     */
+    static damage(boss, playSound) {
+        if (!boss || !boss.active) return false;
+
+        boss.health--;
+        boss.isDamaged = true;
+        boss.damageFlashTimer = 15; // Flash for 15 frames
+
+        if (playSound) playSound('enemy_defeat');
+        console.log(`👹 Boss damaged! Health: ${boss.health}/${boss.maxHealth}`);
+
+        if (boss.health <= 0) {
+            boss.active = false;
+            console.log(`👹 BOSS DEFEATED!`);
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Check collision between Mario and boss knees (weak points)
+     * @param {Object} mario - Mario object
+     * @param {Object} boss - Boss object
+     * @returns {boolean} - True if Mario hit a knee from above
+     */
+    static checkKneeCollision(mario, boss) {
+        if (!boss || !boss.active) return false;
+
+        // Check if Mario is jumping down onto knees
+        const isFalling = mario.velocityY > 0;
+
+        // Check left knee
+        const hitLeftKnee = this._isCollidingRectRect(mario, boss.leftKnee) && isFalling;
+
+        // Check right knee
+        const hitRightKnee = this._isCollidingRectRect(mario, boss.rightKnee) && isFalling;
+
+        return hitLeftKnee || hitRightKnee;
+    }
+
+    /**
+     * Check collision between Mario and boss body (damage to Mario)
+     * @param {Object} mario - Mario object
+     * @param {Object} boss - Boss object
+     * @returns {boolean} - True if Mario touched boss body
+     */
+    static checkBodyCollision(mario, boss) {
+        if (!boss || !boss.active) return false;
+
+        return this._isCollidingRectRect(mario, boss);
+    }
+
+    /**
+     * Rectangle-Rectangle collision detection
+     */
+    static _isCollidingRectRect(rect1, rect2) {
+        return rect1.x < rect2.x + rect2.width &&
+               rect1.x + rect1.width > rect2.x &&
+               rect1.y < rect2.y + rect2.height &&
+               rect1.y + rect1.height > rect2.y;
+    }
+}
+
+export default Boss;
diff --git a/src/gameHelpers/MarioEducational/enemies/Catapult.js b/src/gameHelpers/MarioEducational/enemies/Catapult.js
new file mode 100644
index 0000000..f2376d7
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/enemies/Catapult.js
@@ -0,0 +1,347 @@
+/**
+ * Catapult.js
+ * Enemy that launches boulders and stone rain at Mario
+ * Catapults appear in level 4+, Onagers (stronger) in level 5+
+ */
+
+export class Catapult {
+    /**
+     * Generate catapults for a level
+     * @param {Object} level - Level data
+     * @param {number} levelIndex - Level index
+     * @param {number} levelWidth - Width of the level
+     * @param {number} canvasHeight - Canvas height
+     * @returns {Array} - Array of catapult objects
+     */
+    static generate(level, levelIndex, levelWidth, canvasHeight) {
+        const catapults = [];
+
+        let catapultCount = 1; // Always 1 catapult for level 4+
+        let onagerCount = 0;
+
+        // Level 5+ gets onagers
+        if (levelIndex >= 4) {
+            onagerCount = 1; // 1 onager for level 5+
+        }
+
+        const totalCount = catapultCount + onagerCount;
+        console.log(`🏹 Generating ${catapultCount} catapult(s) and ${onagerCount} onager(s) for level ${levelIndex + 1}`);
+
+        for (let i = 0; i < totalCount; i++) {
+            const isOnager = i >= catapultCount; // Onagers come after catapults
+
+            // Place catapults near END of level
+            const nearEndX = levelWidth * 0.7; // 70% through level
+            const catapultX = nearEndX + (i * 300) + Math.random() * 200;
+            let catapultY = canvasHeight - 100; // Default: on background ground
+
+            // Check if there's a platform, wall, or stair above this position
+            const platformAbove = this._findPlatformAbove(catapultX, catapultY, level.platforms || []);
+            const wallAbove = this._findWallAbove(catapultX, catapultY, level.walls || []);
+            const stairAbove = this._findStairAbove(catapultX, catapultY, level.stairs || []);
+
+            // Choose the lowest obstacle (closest to ground = highest Y value)
+            const obstacles = [platformAbove, wallAbove, stairAbove].filter(obs => obs !== null);
+
+            if (obstacles.length > 0) {
+                const obstacleAbove = obstacles.reduce((lowest, current) =>
+                    current.y > lowest.y ? current : lowest
+                );
+                catapultY = obstacleAbove.y - 80; // 80 is catapult height
+                console.log(`🏹 Catapult moved to obstacle at y=${catapultY.toFixed(0)}`);
+            }
+
+            catapults.push({
+                x: catapultX,
+                y: catapultY,
+                width: 60,
+                height: 80,
+                color: isOnager ? '#654321' : '#8B4513',
+                lastShot: 0,
+                shootCooldown: isOnager ? 6000 + Math.random() * 2000 : 4000 + Math.random() * 2000,
+                type: isOnager ? 'onager' : 'catapult',
+                isOnager: isOnager,
+                armAngle: 0 // For rendering
+            });
+
+            console.log(`${isOnager ? '🏛️' : '🏹'} ${isOnager ? 'Onager' : 'Catapult'} placed at x=${catapultX.toFixed(0)}, y=${catapultY.toFixed(0)}`);
+        }
+
+        return catapults;
+    }
+
+    /**
+     * Find platform above a position
+     */
+    static _findPlatformAbove(x, groundY, platforms) {
+        let bestPlatform = null;
+        let lowestY = 0;
+
+        platforms.forEach(platform => {
+            const catapultLeft = x;
+            const catapultRight = x + 60;
+            const platformLeft = platform.x;
+            const platformRight = platform.x + platform.width;
+
+            const hasHorizontalOverlap = catapultLeft < platformRight && catapultRight > platformLeft;
+
+            if (hasHorizontalOverlap && platform.y < groundY && platform.y > lowestY) {
+                bestPlatform = platform;
+                lowestY = platform.y;
+            }
+        });
+
+        return bestPlatform;
+    }
+
+    /**
+     * Find wall above a position
+     */
+    static _findWallAbove(x, groundY, walls) {
+        let bestWall = null;
+        let lowestY = 0;
+
+        walls.forEach(wall => {
+            const catapultLeft = x;
+            const catapultRight = x + 60;
+            const wallLeft = wall.x;
+            const wallRight = wall.x + wall.width;
+
+            const hasHorizontalOverlap = catapultLeft < wallRight && catapultRight > wallLeft;
+
+            if (hasHorizontalOverlap && wall.y < groundY && wall.y > lowestY) {
+                bestWall = wall;
+                lowestY = wall.y;
+            }
+        });
+
+        return bestWall;
+    }
+
+    /**
+     * Find stair above a position
+     */
+    static _findStairAbove(x, groundY, stairs) {
+        let bestStair = null;
+        let lowestY = 0;
+
+        stairs.forEach(stair => {
+            const catapultLeft = x;
+            const catapultRight = x + 60;
+            const stairLeft = stair.x;
+            const stairRight = stair.x + stair.width;
+
+            const hasHorizontalOverlap = catapultLeft < stairRight && catapultRight > stairLeft;
+
+            if (hasHorizontalOverlap && stair.y < groundY && stair.y > lowestY) {
+                bestStair = stair;
+                lowestY = stair.y;
+            }
+        });
+
+        return bestStair;
+    }
+
+    /**
+     * Update all catapults
+     * @param {Array} catapults - Array of catapults
+     * @param {Object} mario - Mario object
+     * @param {Array} boulders - Boulders array
+     * @param {Array} stones - Stones array (for onagers)
+     * @param {Function} playSound - Sound callback
+     */
+    static update(catapults, mario, boulders, stones, playSound) {
+        const currentTime = Date.now();
+
+        catapults.forEach(catapult => {
+            // Arm animation
+            catapult.armAngle = Math.sin(Date.now() / 200) * 0.2;
+
+            // Check if it's time to shoot
+            if (currentTime - catapult.lastShot > catapult.shootCooldown) {
+                const distanceToMario = Math.abs(catapult.x - mario.x);
+
+                // Catapult shoots boulders (single target)
+                if (!catapult.isOnager && distanceToMario < 600) {
+                    // Calculate trajectory to Mario
+                    const dx = mario.x - catapult.x;
+                    const dy = mario.y - catapult.y;
+                    const distance = Math.sqrt(dx * dx + dy * dy);
+
+                    const speed = 8;
+                    const velocityX = (dx / distance) * speed;
+                    const velocityY = (dy / distance) * speed;
+
+                    boulders.push({
+                        x: catapult.x + catapult.width / 2,
+                        y: catapult.y,
+                        velocityX: velocityX,
+                        velocityY: velocityY,
+                        radius: 20,
+                        type: 'boulder',
+                        launched: true
+                    });
+
+                    catapult.lastShot = currentTime;
+                    if (playSound) playSound('jump'); // Boulder launch sound
+                    console.log(`🪨 Catapult launched boulder towards Mario!`);
+                }
+                // Onager shoots stone rain (area attack)
+                else if (catapult.isOnager && distanceToMario < 800) {
+                    // Create stone rain above Mario's area
+                    const stoneCount = 8 + Math.floor(Math.random() * 5); // 8-12 stones
+
+                    for (let i = 0; i < stoneCount; i++) {
+                        const offsetX = (Math.random() - 0.5) * 400; // Spread 400px around Mario
+
+                        stones.push({
+                            x: mario.x + offsetX,
+                            y: -50 - Math.random() * 100, // Start above screen
+                            velocityX: (Math.random() - 0.5) * 2,
+                            velocityY: 2 + Math.random() * 3,
+                            width: 15 + Math.random() * 10,
+                            height: 15 + Math.random() * 10,
+                            type: 'stone',
+                            rotation: Math.random() * Math.PI * 2
+                        });
+                    }
+
+                    catapult.lastShot = currentTime;
+                    if (playSound) playSound('enemy_defeat'); // Different sound for stone rain
+                    console.log(`☄️ Onager launched stone rain (${stoneCount} stones)!`);
+                }
+            }
+        });
+    }
+
+    /**
+     * Update boulders
+     * @param {Array} boulders - Array of boulders
+     * @param {Object} mario - Mario object
+     * @param {Array} platforms - Platforms for collision
+     * @param {Array} walls - Walls for collision
+     * @param {Function} onImpact - Callback when boulder hits something
+     * @returns {Array} - Updated boulders array
+     */
+    static updateBoulders(boulders, mario, platforms, walls, onImpact) {
+        const GRAVITY = 0.3;
+        const updatedBoulders = [];
+
+        boulders.forEach((boulder, index) => {
+            // Apply physics
+            boulder.velocityY += GRAVITY;
+            boulder.x += boulder.velocityX;
+            boulder.y += boulder.velocityY;
+
+            // Check collision with platforms
+            let hitPlatform = false;
+            platforms.forEach((platform, platformIndex) => {
+                if (this._isCollidingCircleRect(boulder, platform)) {
+                    hitPlatform = true;
+                    if (onImpact) {
+                        onImpact(boulder, index, boulder.x, boulder.y, platform, platformIndex, 'platform');
+                    }
+                }
+            });
+
+            // Check collision with walls
+            let hitWall = false;
+            walls.forEach((wall, wallIndex) => {
+                if (this._isCollidingCircleRect(boulder, wall)) {
+                    hitWall = true;
+                    if (onImpact) {
+                        onImpact(boulder, index, boulder.x, boulder.y, wall, wallIndex, 'wall');
+                    }
+                }
+            });
+
+            // Check collision with Mario
+            if (this._isCollidingCircleRect(boulder, mario)) {
+                if (onImpact) {
+                    onImpact(boulder, index, boulder.x, boulder.y, mario, -1, 'mario');
+                }
+                return; // Remove boulder
+            }
+
+            // Remove if out of bounds or hit something
+            if (!hitPlatform && !hitWall && boulder.y < 1000) {
+                updatedBoulders.push(boulder);
+            }
+        });
+
+        return updatedBoulders;
+    }
+
+    /**
+     * Update stones (stone rain)
+     * @param {Array} stones - Array of stones
+     * @param {Object} mario - Mario object
+     * @param {Array} platforms - Platforms for collision
+     * @param {Function} onImpact - Callback when stone hits something
+     * @returns {Array} - Updated stones array
+     */
+    static updateStones(stones, mario, platforms, onImpact) {
+        const GRAVITY = 0.5;
+        const updatedStones = [];
+
+        stones.forEach((stone, index) => {
+            // Apply physics
+            stone.velocityY += GRAVITY;
+            stone.x += stone.velocityX;
+            stone.y += stone.velocityY;
+            stone.rotation += 0.1;
+
+            // Check collision with platforms
+            let hitPlatform = false;
+            platforms.forEach(platform => {
+                if (this._isCollidingRectRect(stone, platform)) {
+                    hitPlatform = true;
+                    if (onImpact) {
+                        onImpact(stone, index, 'platform');
+                    }
+                }
+            });
+
+            // Check collision with Mario
+            if (this._isCollidingRectRect(stone, mario)) {
+                if (onImpact) {
+                    onImpact(stone, index, 'mario');
+                }
+                return; // Remove stone
+            }
+
+            // Keep stone if not hit and still on screen
+            if (!hitPlatform && stone.y < 1000) {
+                updatedStones.push(stone);
+            }
+        });
+
+        return updatedStones;
+    }
+
+    /**
+     * Circle-Rectangle collision detection
+     */
+    static _isCollidingCircleRect(circle, rect) {
+        const closestX = Math.max(rect.x, Math.min(circle.x, rect.x + rect.width));
+        const closestY = Math.max(rect.y, Math.min(circle.y, rect.y + rect.height));
+
+        const distanceX = circle.x - closestX;
+        const distanceY = circle.y - closestY;
+
+        const distanceSquared = distanceX * distanceX + distanceY * distanceY;
+        return distanceSquared < (circle.radius * circle.radius);
+    }
+
+    /**
+     * Rectangle-Rectangle collision detection
+     */
+    static _isCollidingRectRect(rect1, rect2) {
+        return rect1.x < rect2.x + rect2.width &&
+               rect1.x + rect1.width > rect2.x &&
+               rect1.y < rect2.y + rect2.height &&
+               rect1.y + rect1.height > rect2.y;
+    }
+}
+
+export default Catapult;
diff --git a/src/gameHelpers/MarioEducational/enemies/FlyingEye.js b/src/gameHelpers/MarioEducational/enemies/FlyingEye.js
new file mode 100644
index 0000000..0cbc342
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/enemies/FlyingEye.js
@@ -0,0 +1,187 @@
+/**
+ * FlyingEye.js
+ * Flying enemy that chases Mario and performs dash attacks
+ * Appears in level 5+
+ */
+
+export class FlyingEye {
+    /**
+     * Generate flying eyes for a level
+     * @param {Object} level - Level data
+     * @param {number} difficulty - Difficulty level
+     * @returns {Array} - Array of flying eye objects
+     */
+    static generate(level, difficulty) {
+        const eyes = [];
+        const eyeCount = Math.min(4, Math.max(3, difficulty - 2)); // 3-4 flying eyes
+        console.log(`👁️ Generating ${eyeCount} flying eyes for level 5+`);
+
+        for (let i = 0; i < eyeCount; i++) {
+            // Eyes spawn in the middle-upper area of the level
+            const eyeX = 300 + (i * 400) + Math.random() * 200; // Spread across level
+            const eyeY = 100 + Math.random() * 150; // Upper area of screen
+
+            eyes.push({
+                x: eyeX,
+                y: eyeY,
+                width: 30,
+                height: 30,
+                velocityX: (Math.random() - 0.5) * 2, // Random horizontal drift -1 to +1
+                velocityY: (Math.random() - 0.5) * 2, // Random vertical drift -1 to +1
+                color: '#DC143C', // Crimson red
+                pupilColor: '#000000', // Black pupil
+                type: 'flying_eye',
+                health: 1,
+                maxHealth: 1,
+                // AI behavior properties
+                chaseDistance: 200, // Start chasing Mario within 200px
+                chaseSpeed: 3.5, // Faster chase speed
+                idleSpeed: 1.2, // Faster idle movement
+                lastDirectionChange: Date.now(),
+                directionChangeInterval: 2000 + Math.random() * 3000, // Change direction every 2-5 seconds
+                isChasing: false,
+                // Dash behavior
+                dashCooldown: 0,
+                dashDuration: 0,
+                isDashing: false,
+                dashSpeed: 8, // Very fast dash
+                lastDashTime: Date.now(),
+                dashInterval: 3000 + Math.random() * 2000, // Dash every 3-5 seconds
+                // Visual properties
+                blinkTimer: 0,
+                isBlinking: false
+            });
+
+            console.log(`👁️ Flying eye ${i + 1} placed at x=${eyeX.toFixed(0)}, y=${eyeY.toFixed(0)}`);
+        }
+
+        return eyes;
+    }
+
+    /**
+     * Update all flying eyes
+     * @param {Array} eyes - Array of flying eyes
+     * @param {Object} mario - Mario object
+     * @param {Function} playSound - Sound callback
+     */
+    static update(eyes, mario, playSound) {
+        const currentTime = Date.now();
+
+        eyes.forEach(eye => {
+            const distanceToMario = Math.sqrt(
+                Math.pow(eye.x - mario.x, 2) + Math.pow(eye.y - mario.y, 2)
+            );
+
+            // Blinking animation
+            eye.blinkTimer++;
+            if (eye.blinkTimer > 120) {
+                eye.isBlinking = true;
+            }
+            if (eye.blinkTimer > 125) {
+                eye.isBlinking = false;
+                eye.blinkTimer = 0;
+            }
+
+            // Check if should chase Mario
+            eye.isChasing = distanceToMario < eye.chaseDistance;
+
+            // Dash behavior
+            if (eye.isDashing) {
+                eye.dashDuration--;
+                if (eye.dashDuration <= 0) {
+                    eye.isDashing = false;
+                    eye.dashCooldown = 60; // Cooldown frames after dash
+                }
+            } else if (eye.dashCooldown > 0) {
+                eye.dashCooldown--;
+            } else if (eye.isChasing && currentTime - eye.lastDashTime > eye.dashInterval) {
+                // Start dash towards Mario
+                eye.isDashing = true;
+                eye.dashDuration = 30; // 30 frames of dash
+                eye.lastDashTime = currentTime;
+
+                // Set dash velocity towards Mario
+                const dx = mario.x - eye.x;
+                const dy = mario.y - eye.y;
+                const distance = Math.sqrt(dx * dx + dy * dy);
+                eye.velocityX = (dx / distance) * eye.dashSpeed;
+                eye.velocityY = (dy / distance) * eye.dashSpeed;
+
+                console.log(`👁️ Flying eye dashes towards Mario!`);
+            }
+
+            // Movement behavior
+            if (eye.isDashing) {
+                // Continue dash movement
+                eye.x += eye.velocityX;
+                eye.y += eye.velocityY;
+            } else if (eye.isChasing) {
+                // Chase Mario
+                const dx = mario.x - eye.x;
+                const dy = mario.y - eye.y;
+                const distance = Math.sqrt(dx * dx + dy * dy);
+
+                eye.velocityX = (dx / distance) * eye.chaseSpeed;
+                eye.velocityY = (dy / distance) * eye.chaseSpeed;
+
+                eye.x += eye.velocityX;
+                eye.y += eye.velocityY;
+            } else {
+                // Idle wandering
+                if (currentTime - eye.lastDirectionChange > eye.directionChangeInterval) {
+                    eye.velocityX = (Math.random() - 0.5) * eye.idleSpeed * 2;
+                    eye.velocityY = (Math.random() - 0.5) * eye.idleSpeed * 2;
+                    eye.lastDirectionChange = currentTime;
+                }
+
+                eye.x += eye.velocityX;
+                eye.y += eye.velocityY;
+            }
+
+            // Keep eyes within bounds (with some margin)
+            if (eye.x < 50) {
+                eye.x = 50;
+                eye.velocityX = Math.abs(eye.velocityX);
+            }
+            if (eye.y < 50) {
+                eye.y = 50;
+                eye.velocityY = Math.abs(eye.velocityY);
+            }
+            if (eye.y > 400) {
+                eye.y = 400;
+                eye.velocityY = -Math.abs(eye.velocityY);
+            }
+        });
+    }
+
+    /**
+     * Check collision between Mario and flying eyes
+     * @param {Object} mario - Mario object
+     * @param {Array} eyes - Array of flying eyes
+     * @returns {Object|null} - Colliding eye or null
+     */
+    static checkCollision(mario, eyes) {
+        for (const eye of eyes) {
+            // Simple rectangle collision
+            if (mario.x < eye.x + eye.width &&
+                mario.x + mario.width > eye.x &&
+                mario.y < eye.y + eye.height &&
+                mario.y + mario.height > eye.y) {
+                return eye;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Damage a flying eye
+     * @param {Object} eye - Flying eye to damage
+     * @returns {boolean} - True if eye was killed
+     */
+    static damage(eye) {
+        eye.health--;
+        return eye.health <= 0;
+    }
+}
+
+export default FlyingEye;
diff --git a/src/gameHelpers/MarioEducational/enemies/PiranhaPlant.js b/src/gameHelpers/MarioEducational/enemies/PiranhaPlant.js
new file mode 100644
index 0000000..d3c8a77
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/enemies/PiranhaPlant.js
@@ -0,0 +1,133 @@
+/**
+ * PiranhaPlant.js
+ * Enemy that shoots fireballs at Mario when in range
+ * Appears starting from level 3+
+ */
+
+export class PiranhaPlant {
+    /**
+     * Generate piranha plants for a level
+     * @param {Object} level - Level data
+     * @param {number} difficulty - Difficulty level (1-5)
+     * @returns {Array} - Array of piranha plant objects
+     */
+    static generate(level, difficulty) {
+        const plants = [];
+        const plantCount = Math.min(difficulty - 2, 2); // 0-2 plants for level 3+
+
+        if (plantCount <= 0) return plants;
+
+        for (let i = 0; i < plantCount; i++) {
+            // Find a suitable ground platform for the plant
+            const groundPlatforms = level.platforms.filter(p => p.type === 'ground');
+            if (groundPlatforms.length === 0) continue;
+
+            const platform = groundPlatforms[Math.floor(Math.random() * groundPlatforms.length)];
+            const plantX = platform.x + Math.random() * (platform.width - 30);
+
+            plants.push({
+                x: plantX,
+                y: platform.y - 40, // Plant height above platform
+                width: 30,
+                height: 40,
+                color: '#228B22', // Forest green
+                lastShot: 0,
+                shootCooldown: 2000 + Math.random() * 1000, // 2-3 second intervals
+                type: 'piranha',
+                visible: true,
+                extended: 0, // For animation (how much plant extends from pipe)
+                maxExtension: 40,
+                extending: true
+            });
+
+            console.log(`🌸 Piranha plant placed at x=${plantX.toFixed(0)}`);
+        }
+
+        return plants;
+    }
+
+    /**
+     * Update all piranha plants
+     * @param {Array} plants - Array of piranha plants
+     * @param {Object} mario - Mario object
+     * @param {Array} projectiles - Projectiles array to add new projectiles
+     * @param {Function} playSound - Sound callback
+     */
+    static update(plants, mario, projectiles, playSound) {
+        const currentTime = Date.now();
+
+        plants.forEach(plant => {
+            // Animate plant extension/retraction
+            if (plant.extending) {
+                plant.extended = Math.min(plant.extended + 1, plant.maxExtension);
+                if (plant.extended >= plant.maxExtension) {
+                    plant.extending = false;
+                }
+            } else {
+                plant.extended = Math.max(plant.extended - 1, 0);
+                if (plant.extended <= 0) {
+                    plant.extending = true;
+                }
+            }
+
+            // Check if it's time to shoot
+            if (currentTime - plant.lastShot > plant.shootCooldown) {
+                // Check if Mario is in range (within 400 pixels)
+                const distanceToMario = Math.abs(plant.x - mario.x);
+
+                if (distanceToMario < 400) {
+                    // Shoot projectile towards Mario
+                    const direction = mario.x > plant.x ? 1 : -1;
+
+                    projectiles.push({
+                        x: plant.x + plant.width / 2,
+                        y: plant.y + plant.height / 2,
+                        velocityX: direction * 3, // Projectile speed
+                        velocityY: 0,
+                        radius: 8,
+                        color: '#FF4500', // Orange fireball
+                        type: 'fireball',
+                        life: 200 // 200 frames lifetime
+                    });
+
+                    plant.lastShot = currentTime;
+                    if (playSound) playSound('enemy_defeat'); // Shooting sound
+                    console.log(`🔥 Piranha plant shot fireball towards Mario!`);
+                }
+            }
+        });
+    }
+
+    /**
+     * Check collision between Mario and piranha plants
+     * @param {Object} mario - Mario object
+     * @param {Array} plants - Array of piranha plants
+     * @returns {Object|null} - Colliding plant or null
+     */
+    static checkCollision(mario, plants) {
+        for (const plant of plants) {
+            if (!plant.visible) continue;
+
+            // Only check collision when plant is extended
+            if (plant.extended > 20) {
+                const headY = plant.y - plant.extended;
+                const headRadius = 30;
+
+                // Simple circle-rectangle collision
+                const closestX = Math.max(mario.x, Math.min(plant.x + plant.width / 2, mario.x + mario.width));
+                const closestY = Math.max(mario.y, Math.min(headY, mario.y + mario.height));
+
+                const distanceX = (plant.x + plant.width / 2) - closestX;
+                const distanceY = headY - closestY;
+                const distanceSquared = distanceX * distanceX + distanceY * distanceY;
+
+                if (distanceSquared < headRadius * headRadius) {
+                    return plant;
+                }
+            }
+        }
+        return null;
+    }
+}
+
+export default PiranhaPlant;
diff --git a/src/gameHelpers/MarioEducational/enemies/Projectile.js b/src/gameHelpers/MarioEducational/enemies/Projectile.js
new file mode 100644
index 0000000..233cb1a
--- /dev/null
+++ b/src/gameHelpers/MarioEducational/enemies/Projectile.js
@@ -0,0 +1,147 @@
+/**
+ * Projectile.js
+ * Helper for managing projectiles (fireballs, boss shots, etc.)
+ * Handles movement, collision, and lifetime
+ */
+
+export class Projectile {
+    /**
+     * Update all projectiles
+     * @param {Array} projectiles - Array of projectiles
+     * @param {Object} mario - Mario object
+     * @param {Array} platforms - Platforms for collision
+     * @param {Array} walls - Walls for collision
+     * @param {number} levelWidth - Level width for bounds checking
+     * @param {Function} onMarioHit - Callback when Mario is hit
+     * @param {Function} onObstacleHit - Callback when projectile hits obstacle
+     * @returns {Array} - Updated projectiles array
+     */
+    static update(projectiles, mario, platforms, walls, levelWidth, onMarioHit, onObstacleHit) {
+        const updatedProjectiles = [];
+
+        projectiles.forEach((projectile, index) => {
+            // Update position
+            projectile.x += projectile.velocityX;
+            projectile.y += projectile.velocityY;
+            projectile.life--;
+
+            // Remove projectiles that are off-screen or expired
+            if (projectile.life <= 0 || projectile.x < -50 || projectile.x > levelWidth + 50) {
+                return; // Don't add to updated array (remove)
+            }
+
+            // Check collision with Mario
+            if (this._isCollidingCircleRect(projectile, mario)) {
+                if (onMarioHit) {
+                    onMarioHit(projectile);
+                }
+                return; // Remove projectile
+            }
+
+            // Check collision with walls/platforms
+            const hitPlatform = platforms.some(platform =>
+                this._isCollidingCircleRect(projectile, platform)
+            );
+            const hitWall = walls.some(wall =>
+                this._isCollidingCircleRect(projectile, wall)
+            );
+
+            if (hitPlatform || hitWall) {
+                if (onObstacleHit) {
+                    onObstacleHit(projectile, index, projectile.x, projectile.y);
+                }
+                return; // Remove projectile
+            }
+
+            // Keep projectile if no collision
+            updatedProjectiles.push(projectile);
+        });
+
+        return updatedProjectiles;
+    }
+
+    /**
+     * Create a new projectile
+     * @param {number} x - Start X position
+     * @param {number} y - Start Y position
+     * @param {number} velocityX - Horizontal velocity
+     * @param {number} velocityY - Vertical velocity
+     * @param {Object} options - Additional options (radius, color, type, life)
+     * @returns {Object} - Projectile object
+     */
+    static create(x, y, velocityX, velocityY, options = {}) {
+        return {
+            x: x,
+            y: y,
+            velocityX: velocityX,
+            velocityY: velocityY,
+            radius: options.radius || 8,
+            color: options.color || '#FF4500',
+            type: options.type || 'projectile',
+            life: options.life || 200
+        };
+    }
+
+    /**
+     * Create a projectile aimed at a target
+     * @param {number} fromX - Start X
+     * @param {number} fromY - Start Y
+     * @param {number} toX - Target X
+     * @param {number} toY - Target Y
+     * @param {number} speed - Projectile speed
+     * @param {Object} options - Additional options
+     * @returns {Object} - Projectile object
+     */
+    static createAimed(fromX, fromY, toX, toY, speed, options = {}) {
+        const dx = toX - fromX;
+        const dy = toY - fromY;
+        const distance = Math.sqrt(dx * dx + dy * dy);
+
+        const velocityX = (dx / distance) * speed;
+        const velocityY = (dy / distance) * speed;
+
+        return this.create(fromX, fromY, velocityX, velocityY, options);
+    }
+
+    /**
+     * Circle-Rectangle collision detection
+     * @param {Object} circle - Circle object with x, y, radius
+     * @param {Object} rect - Rectangle object with x, y, width, height
+     * @returns {boolean} - True if colliding
+     */
+    static _isCollidingCircleRect(circle, rect) {
+        const closestX = Math.max(rect.x, Math.min(circle.x, rect.x + rect.width));
+        const closestY = Math.max(rect.y, Math.min(circle.y, rect.y + rect.height));
+
+        const distanceX = circle.x - closestX;
+        const distanceY = circle.y - closestY;
+
+        const distanceSquared = distanceX * distanceX + distanceY * distanceY;
+        return distanceSquared < (circle.radius * circle.radius);
+    }
+
+    /**
+     * Check if a projectile is out of bounds
+     * @param {Object} projectile - Projectile to check
+     * @param {number} levelWidth - Level width
+     * @param {number} canvasHeight - Canvas height
+     * @returns {boolean} - True if out of bounds
+     */
+    static isOutOfBounds(projectile, levelWidth, canvasHeight) {
+        return projectile.x < -50 ||
+               projectile.x > levelWidth + 50 ||
+               projectile.y < -50 ||
+               projectile.y > canvasHeight + 50;
+    }
+
+    /**
+     * Check if projectile has expired
+     * @param {Object} projectile - Projectile to check
+     * @returns {boolean} - True if expired
+     */
+    static isExpired(projectile) {
+        return projectile.life <= 0;
+    }
+}
+
+export default Projectile;
diff --git a/src/games/MarioEducational.js b/src/games/MarioEducational.js
index ba69cc5..f4e4364 100644
--- a/src/games/MarioEducational.js
+++ b/src/games/MarioEducational.js
@@ -1,4 +1,13 @@
 import Module from '../core/Module.js';
+import { sentenceGenerator } from '../gameHelpers/MarioEducational/SentenceGenerator.js';
+import { soundSystem } from '../gameHelpers/MarioEducational/SoundSystem.js';
+import { renderer } from '../gameHelpers/MarioEducational/Renderer.js';
+import PhysicsEngine from '../gameHelpers/MarioEducational/PhysicsEngine.js';
+import PiranhaPlant from '../gameHelpers/MarioEducational/enemies/PiranhaPlant.js';
+import Catapult from '../gameHelpers/MarioEducational/enemies/Catapult.js';
+import FlyingEye from '../gameHelpers/MarioEducational/enemies/FlyingEye.js';
+import Boss from '../gameHelpers/MarioEducational/enemies/Boss.js';
+import Projectile from '../gameHelpers/MarioEducational/enemies/Projectile.js';
 
 /**
  * MarioEducational - 2D Mario-style educational game with question blocks
@@ -106,10 +115,6 @@ class MarioEducational extends Module {
         // UI elements (need to be declared before seal)
         this._uiOverlay = null;
 
-        // Sound system
-        this._audioContext = null;
-        this._sounds = {};
-
         Object.seal(this);
     }
 
@@ -217,7 +222,7 @@ class MarioEducational extends Module {
             this._setupInputHandlers();
 
             // Initialize sound system
-            this._initializeSoundSystem();
+            soundSystem.initialize();
 
             // Generate all levels
             this._generateAllLevels();
@@ -305,7 +310,7 @@ class MarioEducational extends Module {
 
         // Extract sentences from story text
         if (story && typeof story === 'string') {
-            const storySentences = this._splitTextIntoSentences(story);
+            const storySentences = sentenceGenerator.splitTextIntoSentences(story);
             storySentences.forEach(sentence => {
                 this._sentences.push({
                     type: 'story',
@@ -320,7 +325,7 @@ class MarioEducational extends Module {
         if (Array.isArray(texts)) {
             texts.forEach((text, index) => {
                 if (typeof text === 'string') {
-                    const textSentences = this._splitTextIntoSentences(text);
+                    const textSentences = sentenceGenerator.splitTextIntoSentences(text);
                     textSentences.forEach(sentence => {
                         this._sentences.push({
                             type: 'text',
@@ -330,7 +335,7 @@ class MarioEducational extends Module {
                         });
                     });
                 } else if (text.content) {
-                    const textSentences = this._splitTextIntoSentences(text.content);
+                    const textSentences = sentenceGenerator.splitTextIntoSentences(text.content);
                     textSentences.forEach(sentence => {
                         this._sentences.push({
                             type: 'text',
@@ -346,12 +351,14 @@ class MarioEducational extends Module {
         // Add vocabulary as contextual sentences
         Object.entries(vocab).forEach(([word, data]) => {
             if (data.user_language) {
-                const generatedSentence = this._generateSentenceFromWord(word, data);
+                const generatedSentence = sentenceGenerator.generateSentence(word, data);
                 this._sentences.push({
                     type: 'vocabulary',
                     english: generatedSentence.english,
                     translation: generatedSentence.translation,
-                    context: data.type || 'vocabulary'
+                    context: data.type || 'vocabulary',
+                    difficulty: generatedSentence.difficulty,
+                    wordType: generatedSentence.wordType
                 });
             }
         });
@@ -362,93 +369,6 @@ class MarioEducational extends Module {
         console.log(`📝 Extracted ${this._sentences.length} sentences/vocabulary for questions`);
     }
 
-    /**
-     * Generate contextual sentences from vocabulary words
-     * @param {string} word - The vocabulary word
-     * @param {Object} data - Word data including type and translation
-     * @returns {Object} Generated sentence with English and translation
-     */
-    /**
-     * Split long text into individual sentences
-     * @param {string} text - Long text to split
-     * @returns {Array} Array of sentences
-     */
-    _splitTextIntoSentences(text) {
-        if (!text || typeof text !== 'string') return [];
-
-        // Clean the text
-        const cleanText = text.trim();
-
-        // Split by sentence-ending punctuation
-        const sentences = cleanText
-            .split(/[.!?]+/)
-            .map(s => s.trim())
-            .filter(s => s.length > 0)
-            .map(s => {
-                // Add period if sentence doesn't end with punctuation
-                if (!s.match(/[.!?]$/)) {
-                    s += '.';
-                }
-                // Capitalize first letter
-                return s.charAt(0).toUpperCase() + s.slice(1);
-            });
-
-        // Filter out very short sentences (less than 3 words)
-        return sentences.filter(sentence => sentence.split(' ').length >= 3);
-    }
-
-    _generateSentenceFromWord(word, data) {
-        const type = data.type || 'noun';
-        const translation = data.user_language.split('；')[0]; // Use first translation
-
-        // Simple sentence templates based on word type
-        const templates = {
-            'noun': [
-                `This is a ${word}.`,
-                `I see a ${word}.`,
-                `The ${word} is here.`,
-                `Where is the ${word}?`,
-                `I need a ${word}.`
-            ],
-            'adjective': [
-                `The house is ${word}.`,
-                `This looks ${word}.`,
-                `It seems ${word}.`,
-                `How ${word} it is!`,
-                `The weather is ${word}.`
-            ],
-            'verb': [
-                `I ${word} every day.`,
-                `Please ${word} this.`,
-                `Don't ${word} too fast.`,
-                `Can you ${word}?`,
-                `Let's ${word} together.`
-            ],
-            'adverb': [
-                `He walks ${word}.`,
-                `She speaks ${word}.`,
-                `They work ${word}.`,
-                `Do it ${word}.`,
-                `Move ${word}.`
-            ],
-            'preposition': [
-                `The book is ${word} the table.`,
-                `Walk ${word} the street.`,
-                `It's ${word} the house.`,
-                `Look ${word} the window.`,
-                `Go ${word} the door.`
-            ]
-        };
-
-        // Get templates for this word type, fallback to noun if type unknown
-        const typeTemplates = templates[type] || templates['noun'];
-        const randomTemplate = typeTemplates[Math.floor(Math.random() * typeTemplates.length)];
-
-        return {
-            english: randomTemplate,
-            translation: `${translation} - ${randomTemplate.replace(word, `**${word}**`)}`
-        };
-    }
 
     _setupCanvas() {
         this._canvas = document.createElement('canvas');
@@ -482,120 +402,6 @@ class MarioEducational extends Module {
         document.addEventListener('keyup', this._handleKeyUp);
     }
 
-    _initializeSoundSystem() {
-        try {
-            // Initialize Web Audio Context
-            this._audioContext = new (window.AudioContext || window.webkitAudioContext)();
-            console.log('🔊 Sound system initialized');
-
-            // Create sound library
-            this._createSoundLibrary();
-        } catch (error) {
-            console.warn('⚠️ Sound system not available:', error);
-            this._audioContext = null;
-        }
-    }
-
-    _createSoundLibrary() {
-        // Sound definitions with parameters for programmatic generation
-        this._sounds = {
-            jump: { type: 'sweep', frequency: 330, endFrequency: 600, duration: 0.1 },
-            coin: { type: 'bell', frequency: 800, duration: 0.3 },
-            powerup: { type: 'arpeggio', frequencies: [264, 330, 396, 528], duration: 0.6 },
-            enemy_defeat: { type: 'noise_sweep', frequency: 200, endFrequency: 50, duration: 0.2 },
-            question_block: { type: 'sparkle', frequency: 600, endFrequency: 1200, duration: 0.4 },
-            level_complete: { type: 'victory', frequencies: [523, 659, 784, 1047], duration: 1.0 },
-            death: { type: 'descend', frequency: 300, endFrequency: 100, duration: 0.8 },
-            finish_stars: { type: 'magical', frequencies: [880, 1100, 1320, 1760], duration: 2.0 }
-        };
-
-        console.log('🎵 Sound library created with', Object.keys(this._sounds).length, 'sounds');
-    }
-
-    _playSound(soundName, volume = 0.3) {
-        if (!this._audioContext || !this._sounds[soundName]) {
-            return;
-        }
-
-        try {
-            const sound = this._sounds[soundName];
-            const oscillator = this._audioContext.createOscillator();
-            const gainNode = this._audioContext.createGain();
-
-            oscillator.connect(gainNode);
-            gainNode.connect(this._audioContext.destination);
-
-            const currentTime = this._audioContext.currentTime;
-            const duration = sound.duration;
-
-            // Set volume
-            gainNode.gain.setValueAtTime(0, currentTime);
-            gainNode.gain.linearRampToValueAtTime(volume, currentTime + 0.01);
-            gainNode.gain.exponentialRampToValueAtTime(0.01, currentTime + duration);
-
-            // Configure sound based on type
-            switch (sound.type) {
-                case 'sweep':
-                    oscillator.type = 'square';
-                    oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
-                    oscillator.frequency.linearRampToValueAtTime(sound.endFrequency, currentTime + duration);
-                    break;
-
-                case 'bell':
-                    oscillator.type = 'sine';
-                    oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
-                    oscillator.frequency.exponentialRampToValueAtTime(sound.frequency * 0.5, currentTime + duration);
-                    break;
-
-                case 'noise_sweep':
-                    oscillator.type = 'sawtooth';
-                    oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
-                    oscillator.frequency.linearRampToValueAtTime(sound.endFrequency, currentTime + duration);
-                    break;
-
-                case 'sparkle':
-                    oscillator.type = 'triangle';
-                    oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
-                    oscillator.frequency.linearRampToValueAtTime(sound.endFrequency, currentTime + duration * 0.7);
-                    oscillator.frequency.linearRampToValueAtTime(sound.frequency, currentTime + duration);
-                    break;
-
-                case 'descend':
-                    oscillator.type = 'square';
-                    oscillator.frequency.setValueAtTime(sound.frequency, currentTime);
-                    oscillator.frequency.exponentialRampToValueAtTime(sound.endFrequency, currentTime + duration);
-                    break;
-
-                case 'arpeggio':
-                case 'victory':
-                case 'magical':
-                    // For complex sounds, play the first frequency and schedule others
-                    oscillator.type = sound.type === 'magical' ? 'triangle' : 'square';
-                    oscillator.frequency.setValueAtTime(sound.frequencies[0], currentTime);
-
-                    // Schedule frequency changes for arpeggio effect
-                    const noteLength = duration / sound.frequencies.length;
-                    sound.frequencies.forEach((freq, index) => {
-                        if (index > 0) {
-                            oscillator.frequency.setValueAtTime(freq, currentTime + noteLength * index);
-                        }
-                    });
-                    break;
-
-                default:
-                    oscillator.type = 'square';
-                    oscillator.frequency.setValueAtTime(sound.frequency || 440, currentTime);
-            }
-
-            oscillator.start(currentTime);
-            oscillator.stop(currentTime + duration);
-
-            console.log(`🎵 Playing sound: ${soundName}`);
-
-        } catch (error) {
-            console.warn('⚠️ Failed to play sound:', soundName, error);
-        }
-    }
 
     _generateAllLevels() {
         this._levelData = [];
@@ -1341,33 +1147,14 @@ class MarioEducational extends Module {
     }
 
     _generatePiranhaPlants(level, difficulty) {
-        const plantCount = Math.min(difficulty - 2, 2); // 0-2 plants for level 3+
-
-        for (let i = 0; i < plantCount; i++) {
-            // Find a suitable ground platform for the plant
-            const groundPlatforms = level.platforms.filter(p => p.type === 'ground');
-            if (groundPlatforms.length === 0) continue;
-
-            const platform = groundPlatforms[Math.floor(Math.random() * groundPlatforms.length)];
-            const plantX = platform.x + Math.random() * (platform.width - 30);
-
-            level.piranhaPlants = level.piranhaPlants || [];
-            level.piranhaPlants.push({
-                x: plantX,
-                y: platform.y - 40, // Plant height
-                width: 30,
-                height: 40,
-                color: '#228B22', // Forest green
-                lastShot: 0,
-                shootCooldown: 2000 + Math.random() * 1000, // 2-3 second intervals
-                type: 'piranha'
-            });
-
-            console.log(`🌸 Piranha plant placed at x=${plantX.toFixed(0)}`);
-        }
+        level.piranhaPlants = PiranhaPlant.generate(level, difficulty);
     }
 
     _generateCatapults(level, difficulty) {
+        level.catapults = Catapult.generate(level, level.index, this._levelWidth, this._config.canvasHeight);
+    }
+
+    _generateCatapultsOLD(level, difficulty) {
         const { index } = level;
 
         let catapultCount = 1; // Always 1 catapult for level 4+
@@ -1842,326 +1629,45 @@ class MarioEducational extends Module {
     }
 
     _updateMarioMovement() {
-        // Don't update movement during celebration
-        if (this._isCelebrating) return;
-
-        // Horizontal movement
-        if (this._keys['ArrowLeft'] || this._keys['KeyA']) {
-            this._mario.velocityX = -this._config.moveSpeed;
-            this._mario.facing = 'left';
-        } else if (this._keys['ArrowRight'] || this._keys['KeyD']) {
-            this._mario.velocityX = this._config.moveSpeed;
-            this._mario.facing = 'right';
-        } else {
-            this._mario.velocityX *= 0.8; // Friction
-        }
-
-        // Jumping
-        if ((this._keys['ArrowUp'] || this._keys['KeyW'] || this._keys['Space']) && this._mario.onGround) {
-            this._mario.velocityY = this._config.jumpForce;
-            this._mario.onGround = false;
-            this._playSound('jump');
-        }
+        PhysicsEngine.updateMarioMovement(this._mario, this._keys, this._config, this._isCelebrating, (sound) => soundSystem.play(sound));
     }
 
     _updateMarioPhysics() {
-        // Apply gravity
-        this._mario.velocityY += this._config.gravity;
-
-        // Update position
-        this._mario.x += this._mario.velocityX;
-        this._mario.y += this._mario.velocityY;
-
-        // Prevent going off left edge
-        if (this._mario.x < 0) {
-            this._mario.x = 0;
-        }
-
-        // Stop Mario at finish line during celebration
         const level = this._levelData[this._currentLevelIndex];
-        if (this._mario.x > level.endX && this._levelCompleted) {
-            this._mario.x = level.endX;
-            this._mario.velocityX = 0;
-        }
-
-        // Check if Mario fell off the world
-        if (this._mario.y > this._config.canvasHeight + 100) {
-            this._restartLevel();
-        }
+        PhysicsEngine.updateMarioPhysics(this._mario, this._config, level, this._levelCompleted, () => this._restartLevel());
     }
 
     _updateEnemies() {
-        // Don't update enemies during celebration
-        if (this._isCelebrating) return;
-
-        this._enemies.forEach(enemy => {
-            // Store old position for collision detection
-            const oldX = enemy.x;
-            enemy.x += enemy.velocityX;
-
-            // Check wall collisions
-            const hitWall = this._walls.some(wall => {
-                return enemy.x < wall.x + wall.width &&
-                       enemy.x + enemy.width > wall.x &&
-                       enemy.y < wall.y + wall.height &&
-                       enemy.y + enemy.height > wall.y;
-            });
-
-            if (hitWall) {
-                // Reverse position and direction
-                enemy.x = oldX;
-                enemy.velocityX *= -1;
-                console.log(`🧱 Enemy hit wall, reversing direction`);
-            }
-
-            // Simple AI: reverse direction at platform edges
-            const platform = this._platforms.find(p =>
-                enemy.x >= p.x - 10 && enemy.x <= p.x + p.width + 10 &&
-                enemy.y >= p.y - enemy.height - 5 && enemy.y <= p.y + 5
-            );
-
-            if (!platform || enemy.x <= 0 || enemy.x >= this._levelWidth) {
-                enemy.velocityX *= -1;
-            }
-        });
+        PhysicsEngine.updateEnemies(this._enemies, this._walls, this._platforms, this._levelWidth, this._isCelebrating);
     }
 
     _checkCollisions() {
-        // Platform collisions
-        this._mario.onGround = false;
+        const gameState = {
+            platforms: this._platforms,
+            questionBlocks: this._questionBlocks,
+            enemies: this._enemies,
+            walls: this._walls,
+            catapults: this._catapults,
+            piranhaPlants: this._piranhaPlants,
+            boulders: this._boulders
+        };
 
-        this._platforms.forEach(platform => {
-            if (this._isColliding(this._mario, platform)) {
-                // Calculate overlap amounts to determine collision direction
-                const overlapLeft = (this._mario.x + this._mario.width) - platform.x;
-                const overlapRight = (platform.x + platform.width) - this._mario.x;
-                const overlapTop = (this._mario.y + this._mario.height) - platform.y;
-                const overlapBottom = (platform.y + platform.height) - this._mario.y;
+        const callbacks = {
+            onQuestionBlock: (block) => this._hitQuestionBlock(block),
+            onEnemyDefeat: (index) => {
+                this._score += 50;
+                this._enemies.splice(index, 1);
+            },
+            onMarioDeath: () => this._restartLevel(),
+            onAddParticles: (x, y, color) => this._addParticles(x, y, color)
+        };
 
-                // Find the smallest overlap to determine collision side
-                const minOverlap = Math.min(overlapLeft, overlapRight, overlapTop, overlapBottom);
-
-                if (minOverlap === overlapTop && this._mario.velocityY > 0) {
-                    // Landing on top of platform
-                    this._mario.y = platform.y - this._mario.height;
-                    this._mario.velocityY = 0;
-                    this._mario.onGround = true;
-                }
-                else if (minOverlap === overlapBottom && this._mario.velocityY < 0) {
-                    // Hitting platform from below
-                    this._mario.y = platform.y + platform.height;
-                    this._mario.velocityY = 0;
-                }
-                else if (minOverlap === overlapLeft && this._mario.velocityX > 0) {
-                    // Hitting platform from left
-                    this._mario.x = platform.x - this._mario.width;
-                    this._mario.velocityX = 0;
-                }
-                else if (minOverlap === overlapRight && this._mario.velocityX < 0) {
-                    // Hitting platform from right
-                    this._mario.x = platform.x + platform.width;
-                    this._mario.velocityX = 0;
-                }
-            }
-        });
-
-        // Boulder platform collisions (landed boulders act as platforms)
-        this._boulders.forEach(boulder => {
-            if (boulder.hasLanded && this._isColliding(this._mario, boulder)) {
-                // Same collision logic as platforms
-                const overlapLeft = (this._mario.x + this._mario.width) - boulder.x;
-                const overlapRight = (boulder.x + boulder.width) - this._mario.x;
-                const overlapTop = (this._mario.y + this._mario.height) - boulder.y;
-                const overlapBottom = (boulder.y + boulder.height) - this._mario.y;
-                const minOverlap = Math.min(overlapLeft, overlapRight, overlapTop, overlapBottom);
-
-                if (minOverlap === overlapTop && this._mario.velocityY > 0) {
-                    // Landing on top of boulder
-                    this._mario.y = boulder.y - this._mario.height;
-                    this._mario.velocityY = 0;
-                    this._mario.onGround = true;
-                }
-                else if (minOverlap === overlapBottom && this._mario.velocityY < 0) {
-                    // Hitting boulder from below
-                    this._mario.y = boulder.y + boulder.height;
-                    this._mario.velocityY = 0;
-                }
-                else if (minOverlap === overlapLeft && this._mario.velocityX > 0) {
-                    // Hitting boulder from left
-                    this._mario.x = boulder.x - this._mario.width;
-                    this._mario.velocityX = 0;
-                }
-                else if (minOverlap === overlapRight && this._mario.velocityX < 0) {
-                    // Hitting boulder from right
-                    this._mario.x = boulder.x + boulder.width;
-                    this._mario.velocityX = 0;
-                }
-            }
-        });
-
-        // Question block collisions
-        this._questionBlocks.forEach(block => {
-            if (!block.hit && this._isColliding(this._mario, block)) {
-                // Hit from below (jumping into block)
-                if (this._mario.velocityY < 0 &&
-                    this._mario.y > block.y + block.height / 2) {
-                    this._hitQuestionBlock(block);
-                }
-                // Touch from side or top
-                else {
-                    this._hitQuestionBlock(block);
-                }
-            }
-        });
-
-        // Wall collisions
-        this._walls.forEach(wall => {
-            if (this._isColliding(this._mario, wall)) {
-                // Calculate overlap amounts to determine collision direction
-                const overlapLeft = (this._mario.x + this._mario.width) - wall.x;
-                const overlapRight = (wall.x + wall.width) - this._mario.x;
-                const overlapTop = (this._mario.y + this._mario.height) - wall.y;
-                const overlapBottom = (wall.y + wall.height) - this._mario.y;
-
-                // Find the smallest overlap to determine collision side
-                const minOverlap = Math.min(overlapLeft, overlapRight, overlapTop, overlapBottom);
-
-                if (minOverlap === overlapTop && this._mario.velocityY > 0) {
-                    // Landing on top of wall
-                    this._mario.y = wall.y - this._mario.height;
-                    this._mario.velocityY = 0;
-                    this._mario.onGround = true;
-                }
-                else if (minOverlap === overlapBottom && this._mario.velocityY < 0) {
-                    // Hitting wall from below
-                    this._mario.y = wall.y + wall.height;
-                    this._mario.velocityY = 0;
-                }
-                else if (minOverlap === overlapLeft && this._mario.velocityX > 0) {
-                    // Hitting wall from left
-                    this._mario.x = wall.x - this._mario.width;
-                    this._mario.velocityX = 0;
-                }
-                else if (minOverlap === overlapRight && this._mario.velocityX < 0) {
-                    // Hitting wall from right
-                    this._mario.x = wall.x + wall.width;
-                    this._mario.velocityX = 0;
-                }
-            }
-        });
-
-        // Catapult collisions (Mario destroys catapults!)
-        this._catapults.forEach((catapult, index) => {
-            if (this._isColliding(this._mario, catapult)) {
-                console.log(`💥 Mario destroyed catapult! Explosion!`);
-
-                // Create massive explosion effect at catapult center
-                const explosionX = catapult.x + catapult.width / 2;
-                const explosionY = catapult.y + catapult.height / 2;
-
-                // Generate lots of particles flying in all directions
-                for (let i = 0; i < 25; i++) {
-                    const angle = (Math.PI * 2 * i) / 25; // Spread particles in circle
-                    const speed = 3 + Math.random() * 4; // Random speed 3-7
-                    const particleColor = ['#8B4513', '#654321', '#D2691E', '#FF4500', '#FFD700'][Math.floor(Math.random() * 5)];
-
-                    this._particles.push({
-                        x: explosionX,
-                        y: explosionY,
-                        velocityX: Math.cos(angle) * speed,
-                        velocityY: Math.sin(angle) * speed,
-                        color: particleColor,
-                        life: 60 + Math.random() * 30, // Live 60-90 frames
-                        maxLife: 60 + Math.random() * 30,
-                        size: 3 + Math.random() * 4 // Size 3-7
-                    });
-                }
-
-                // Remove the destroyed catapult
-                this._catapults.splice(index, 1);
-
-                // Play destruction sound and bounce Mario up slightly
-                this._playSound('enemy_defeat');
-                this._mario.velocityY = this._config.jumpForce * 0.5; // Small bounce from impact
-
-                console.log(`🏹 Catapult destroyed! ${this._catapults.length} catapults remaining.`);
-            }
-        });
-
-        // Enemy collisions
-        this._enemies.forEach((enemy, index) => {
-            if (this._isColliding(this._mario, enemy)) {
-                // Calculate overlap to determine if Mario is stomping enemy
-                const overlapTop = (this._mario.y + this._mario.height) - enemy.y;
-                const overlapBottom = (enemy.y + enemy.height) - this._mario.y;
-
-                // Stomp enemy if Mario is coming from above
-                if (this._mario.velocityY > 0 && overlapTop < overlapBottom) {
-                    if (enemy.hasHelmet) {
-                        // Can't stomp helmet enemies! Mario bounces off
-                        this._mario.velocityY = this._config.jumpForce * 0.7; // Big bounce back
-                        this._addParticles(enemy.x, enemy.y, '#C0C0C0'); // Silver particles
-                        this._playSound('jump'); // Bounce sound
-                        console.log(`🛡️ Mario bounced off helmet enemy!`);
-                    } else {
-                        // Normal enemy - can be stomped
-                        this._enemies.splice(index, 1);
-                        this._mario.velocityY = this._config.jumpForce / 2; // Small bounce
-                        // NO SCORE for killing enemies anymore!
-                        this._addParticles(enemy.x, enemy.y, '#FFD700');
-                        this._playSound('enemy_defeat');
-                        console.log(`🦶 Mario stomped normal enemy! (No score)`);
-                    }
-                } else {
-                    // Mario gets hurt by side/bottom collision
-                    console.log(`💥 Mario hit by enemy - restarting level`);
-                    this._restartLevel();
-                }
-            }
-        });
-
-        // Check piranha plant collisions (skip flattened plants)
-        this._piranhaPlants.forEach((plant, index) => {
-            if (!plant.flattened && this._isColliding(this._mario, plant)) {
-                // Calculate overlap to determine if Mario is stomping plant
-                const overlapTop = (this._mario.y + this._mario.height) - plant.y;
-                const overlapBottom = (plant.y + plant.height) - this._mario.y;
-
-                // Stomp plant if Mario is coming from above
-                if (this._mario.velocityY > 0 && overlapTop < overlapBottom) {
-                    // Flatten the plant instead of removing it
-                    plant.flattened = true;
-                    plant.height = 5; // Very flat
-                    plant.y += 35; // Move to ground level (original height was 40, new is 5)
-                    plant.shootCooldown = Infinity; // Stop shooting
-                    this._mario.velocityY = this._config.jumpForce / 2; // Small bounce
-                    this._addParticles(plant.x, plant.y, '#228B22'); // Green particles
-                    this._playSound('enemy_defeat');
-                    console.log(`🌸 Mario flattened piranha plant!`);
-                } else {
-                    // Mario gets hurt by side collision
-                    console.log(`💥 Mario hit by piranha plant - restarting level`);
-                    this._restartLevel();
-                }
-            }
-        });
-
-        // Check walking on flattened plants (for particles)
-        this._piranhaPlants.forEach((plant, index) => {
-            if (plant.flattened && this._isColliding(this._mario, plant)) {
-                // Mario is standing on a flattened plant - add particles occasionally
-                if (Math.random() < 0.1) { // 10% chance per frame for particles
-                    this._addSmallParticles(plant.x + Math.random() * plant.width, plant.y, '#8B4513'); // Brown dust particles
-                }
-            }
-        });
+        PhysicsEngine.checkCollisions(this._mario, gameState, callbacks);
     }
 
+
     _isColliding(rect1, rect2) {
-        return rect1.x < rect2.x + rect2.width &&
-               rect1.x + rect1.width > rect2.x &&
-               rect1.y < rect2.y + rect2.height &&
-               rect1.y + rect1.height > rect2.y;
+        return PhysicsEngine.isColliding(rect1, rect2);
     }
 
     _hitQuestionBlock(block) {
@@ -2173,7 +1679,7 @@ class MarioEducational extends Module {
 
         this._score += 100; // Increased points for question blocks
         this._addParticles(block.x, block.y, '#FFD700');
-        this._playSound('question_block');
+        soundSystem.play('question_block');
 
         // Show question dialog
         this._showQuestionDialog(block.sentence);
@@ -2291,300 +1797,33 @@ class MarioEducational extends Module {
     }
 
     _updatePiranhaPlants() {
-        const currentTime = Date.now();
-
-        this._piranhaPlants.forEach(plant => {
-            // Check if it's time to shoot
-            if (currentTime - plant.lastShot > plant.shootCooldown) {
-                // Check if Mario is in range (within 400 pixels)
-                const distanceToMario = Math.abs(plant.x - this._mario.x);
-
-                if (distanceToMario < 400) {
-                    // Shoot projectile towards Mario
-                    const direction = this._mario.x > plant.x ? 1 : -1;
-
-                    this._projectiles.push({
-                        x: plant.x + plant.width / 2,
-                        y: plant.y + plant.height / 2,
-                        velocityX: direction * 3, // Projectile speed
-                        velocityY: 0,
-                        width: 8,
-                        height: 8,
-                        color: '#FF4500', // Orange fireball
-                        type: 'fireball',
-                        life: 200 // 200 frames lifetime
-                    });
-
-                    plant.lastShot = currentTime;
-                    this._playSound('enemy_defeat'); // Shooting sound
-                    console.log(`🔥 Piranha plant shot fireball towards Mario!`);
-                }
-            }
-        });
+        PiranhaPlant.update(this._piranhaPlants, this._mario, this._projectiles, (sound) => soundSystem.play(sound));
     }
 
     _updateProjectiles() {
-        // Update projectile positions
-        this._projectiles.forEach((projectile, index) => {
-            projectile.x += projectile.velocityX;
-            projectile.y += projectile.velocityY;
-            projectile.life--;
-
-            // Remove projectiles that are off-screen or expired
-            if (projectile.life <= 0 || projectile.x < -50 || projectile.x > this._levelWidth + 50) {
-                this._projectiles.splice(index, 1);
-                return;
-            }
-
-            // Check collision with Mario
-            if (this._isColliding(this._mario, projectile)) {
-                console.log(`🔥 Mario hit by projectile - restarting level`);
-                this._restartLevel();
-                return;
-            }
-
-            // Check collision with walls/platforms
-            const hitObstacle = this._platforms.some(platform => this._isColliding(projectile, platform)) ||
-                               this._walls.some(wall => this._isColliding(projectile, wall));
-
-            if (hitObstacle) {
-                this._projectiles.splice(index, 1);
-                this._addParticles(projectile.x, projectile.y, '#FF4500');
-                console.log(`💥 Projectile hit obstacle`);
-            }
-        });
+        this._projectiles = Projectile.update(
+            this._projectiles,
+            this._mario,
+            this._platforms,
+            this._walls,
+            this._levelWidth,
+            () => { console.log(`🔥 Mario hit by projectile`); this._restartLevel(); },
+            (proj, idx, x, y) => this._addParticles(x, y, '#FF4500')
+        );
     }
 
     _updateCatapults() {
-        const currentTime = Date.now();
-
-        this._catapults.forEach(catapult => {
-            // Check if it's time to shoot
-            if (currentTime - catapult.lastShot > catapult.shootCooldown) {
-                // Target Mario's position with imperfect aim (randomness)
-                const aimOffset = 100 + Math.random() * 150; // 100-250 pixel spread
-                const aimDirection = Math.random() < 0.5 ? -1 : 1;
-                const targetX = this._mario.x + (aimOffset * aimDirection);
-                const targetY = this._config.canvasHeight - 50; // Ground level
-
-                // ONAGER ONLY: Check minimum range - don't fire if Mario is too close
-                if (catapult.isOnager) {
-                    const distanceToMario = Math.abs(catapult.x - this._mario.x);
-                    const minimumRange = 300; // Onager won't fire if Mario is within 300px
-
-                    if (distanceToMario < minimumRange) {
-                        console.log(`🏛️ Onager held fire - Mario too close! Distance: ${distanceToMario.toFixed(0)}px (min: ${minimumRange}px)`);
-                        return; // Skip this shot, Mario is too close
-                    }
-                }
-
-                // Check if there's a clear line of sight (no platform blocking)
-                if (!this._hasLineOfSight(catapult, targetX, targetY)) {
-                    console.log(`🚫 ${catapult.type} blocked by obstacle, skipping shot`);
-                    return; // Skip this shot, try again next time
-                }
-
-                if (catapult.isOnager) {
-                    // ONAGER: Fire 8 small stones in spread pattern
-                    console.log(`🏛️ Onager firing stone rain!`);
-
-                    for (let stone = 0; stone < 8; stone++) {
-                        // Much more random targeting for fear factor
-                        const randomSpreadX = (Math.random() - 0.5) * 400; // ±200px spread
-                        const randomSpreadY = (Math.random() - 0.5) * 100; // ±50px spread
-                        const stoneTargetX = targetX + randomSpreadX;
-                        const stoneTargetY = targetY + randomSpreadY;
-
-                        // Calculate trajectory for small stone
-                        const deltaX = stoneTargetX - catapult.x;
-                        const deltaY = stoneTargetY - catapult.y;
-                        const time = 5 + Math.random() * 2; // 5-7 seconds flight time (varied)
-                        const velocityX = deltaX / (time * 60);
-                        const velocityY = (deltaY - 0.5 * 0.015 * time * time * 60 * 60) / (time * 60); // Slightly more gravity
-
-                        this._stones.push({
-                            x: catapult.x + 30 + (Math.random() - 0.5) * 20, // Spread launch point
-                            y: catapult.y - 10 + (Math.random() - 0.5) * 10,
-                            width: 8, // Much smaller than boulders
-                            height: 8,
-                            velocityX: velocityX,
-                            velocityY: velocityY,
-                            color: '#A0522D', // Brown stone color
-                            type: 'stone',
-                            sourceCatapultX: catapult.x,
-                            sourceCatapultY: catapult.y
-                        });
-                    }
-
-                    catapult.lastShot = currentTime;
-                    this._playSound('enemy_defeat'); // Different sound for stone rain
-                    console.log(`🏛️ Onager fired 8 stones in spread pattern!`);
-                } else {
-                    // CATAPULT: Fire single boulder (original behavior)
-                    const deltaX = targetX - catapult.x;
-                    const deltaY = targetY - catapult.y;
-                    const time = 7.5; // 7.5 seconds flight time
-                    const velocityX = deltaX / (time * 60);
-                    const velocityY = (deltaY - 0.5 * 0.01 * time * time * 60 * 60) / (time * 60);
-
-                    this._boulders.push({
-                        x: catapult.x + 30,
-                        y: catapult.y - 10,
-                        width: 25,
-                        height: 25,
-                        velocityX: velocityX,
-                        velocityY: velocityY,
-                        color: '#696969', // Dark gray
-                        type: 'boulder',
-                        hasLanded: false,
-                        sourceCatapultX: catapult.x,
-                        sourceCatapultY: catapult.y,
-                        health: 2,
-                        maxHealth: 2
-                    });
-
-                    catapult.lastShot = currentTime;
-                    this._playSound('jump'); // Boulder launch sound
-                    console.log(`🏹 Catapult fired boulder towards x=${targetX.toFixed(0)}`);
-                }
-            }
-        });
+        Catapult.update(this._catapults, this._mario, this._boulders, this._stones, (sound) => soundSystem.play(sound));
     }
 
     _updateBoulders() {
-        this._boulders.forEach((boulder, index) => {
-            if (boulder.hasLanded) return; // Don't update landed boulders
-
-            // Apply gravity and movement (MUCH slower with very light gravity)
-            boulder.velocityY += 0.01; // Ultra-light gravity so boulders can actually fly properly
-            boulder.x += boulder.velocityX;
-            boulder.y += boulder.velocityY;
-
-            // Check ground collision
-            const groundLevel = this._config.canvasHeight - 50;
-            if (boulder.y + boulder.height >= groundLevel) {
-                this._handleBoulderImpact(boulder, index, boulder.x, groundLevel - boulder.height);
-                return;
+        this._boulders = Catapult.updateBoulders(
+            this._boulders, this._mario, this._platforms, this._walls,
+            (boulder, idx, x, y, obj, objIdx, type) => {
+                this._addParticles(x, y, '#808080');
+                if (type === 'mario') this._restartLevel();
             }
-
-            // Check collision with platforms, walls, stairs
-            let hasHit = false;
-
-            // Check platforms
-            this._platforms.forEach((platform, platformIndex) => {
-                if (!hasHit && this._isColliding(boulder, platform)) {
-                    this._handleBoulderImpact(boulder, index, boulder.x, platform.y - boulder.height, platform, platformIndex);
-                    hasHit = true;
-                }
-            });
-
-            // Check walls (boulder damages walls)
-            if (!hasHit) {
-                this._walls.forEach((wall, wallIndex) => {
-                    if (!hasHit && this._isColliding(boulder, wall)) {
-                        console.log(`🪨 Boulder hit wall! Wall damage system activated.`);
-
-                        // Boulder is DESTROYED when hitting wall
-                        this._addParticles(boulder.x + boulder.width/2, boulder.y + boulder.height/2, '#696969');
-                        this._boulders.splice(index, 1);
-                        this._playSound('enemy_defeat');
-                        console.log(`💥 Boulder destroyed on wall impact`);
-
-                        // Wall takes damage
-                        wall.health--;
-                        console.log(`🧱 Wall health: ${wall.health}/${wall.maxHealth}`);
-
-                        if (wall.health <= 0) {
-                            // Wall is destroyed
-                            this._addParticles(wall.x + wall.width/2, wall.y + wall.height/2, '#8B4513');
-                            this._walls.splice(wallIndex, 1);
-                            console.log(`💥 Wall destroyed!`);
-                        } else {
-                            // Visual damage - change color to show damage
-                            if (wall.health === 2) {
-                                wall.color = '#A0522D'; // Slightly damaged - darker brown
-                            } else if (wall.health === 1) {
-                                wall.color = '#654321'; // Heavily damaged - dark brown
-                            }
-                            console.log(`🩹 Wall damaged but still standing`);
-                        }
-
-                        hasHit = true;
-                    }
-                });
-            }
-
-            // Check collision with catapults (but NOT the source catapult)
-            if (!hasHit) {
-                this._catapults.forEach((catapult, catapultIndex) => {
-                    // Don't collide with the catapult that fired this boulder
-                    const isSameCatapult = Math.abs(boulder.sourceCatapultX - catapult.x) < 10 &&
-                                          Math.abs(boulder.sourceCatapultY - catapult.y) < 10;
-
-                    if (!hasHit && !isSameCatapult && this._isColliding(boulder, catapult)) {
-                        // Boulder hits a different catapult - land on top
-                        this._handleBoulderImpact(boulder, index, boulder.x, catapult.y - boulder.height, catapult, catapultIndex, 'catapult');
-                        hasHit = true;
-                        console.log(`🪨 Boulder hit different catapult!`);
-                    }
-                });
-            }
-
-            // Check collision with Mario (boulder resets level like enemies!)
-            if (!hasHit && this._isColliding(boulder, this._mario)) {
-                console.log(`💀 Boulder hit Mario! Respawning at level start.`);
-                this._addParticles(this._mario.x, this._mario.y, '#FF0000'); // Red death particles
-                this._playSound('enemy_defeat');
-
-                // Reset Mario to start position like other enemy deaths
-                const level = this._levelData[this._currentLevelIndex];
-                this._mario.x = level.startX;
-                this._mario.y = level.startY;
-                this._mario.velocityX = 0;
-                this._mario.velocityY = 0;
-
-                // Boulder lands after hitting Mario
-                this._handleBoulderImpact(boulder, index, boulder.x, this._config.canvasHeight - 75);
-                hasHit = true;
-                return;
-            }
-
-            // Check collision with OTHER boulders (boulder-to-boulder damage system)
-            if (!hasHit) {
-                this._boulders.forEach((otherBoulder, otherIndex) => {
-                    if (!hasHit && otherIndex !== index && otherBoulder.hasLanded && this._isColliding(boulder, otherBoulder)) {
-                        console.log(`🪨 Flying boulder hit landed boulder! Damage system activated.`);
-
-                        // Flying boulder is DESTROYED (removed completely)
-                        this._addParticles(boulder.x + boulder.width/2, boulder.y + boulder.height/2, '#696969');
-                        this._boulders.splice(index, 1);
-                        this._playSound('enemy_defeat');
-                        console.log(`💥 Flying boulder destroyed on impact`);
-
-                        // Landed boulder takes damage
-                        otherBoulder.health--;
-                        console.log(`🩹 Landed boulder health: ${otherBoulder.health}/${otherBoulder.maxHealth}`);
-
-                        if (otherBoulder.health <= 0) {
-                            // Landed boulder is destroyed
-                            this._addParticles(otherBoulder.x + otherBoulder.width/2, otherBoulder.y + otherBoulder.height/2, '#8B4513');
-                            this._boulders.splice(otherIndex, 1);
-                            console.log(`💥 Landed boulder destroyed!`);
-                        } else {
-                            // Visual damage - change color to show damage
-                            otherBoulder.color = otherBoulder.health === 1 ? '#A0522D' : '#696969'; // Darker when damaged
-                        }
-
-                        hasHit = true;
-                    }
-                });
-            }
-
-            // Remove boulders that go off-screen
-            if (boulder.x < -100 || boulder.x > this._levelWidth + 100 || boulder.y > this._config.canvasHeight + 100) {
-                this._boulders.splice(index, 1);
-            }
-        });
+        );
     }
 
     _handleBoulderImpact(boulder, boulderIndex, impactX, impactY, hitObject = null, hitObjectIndex = -1, hitType = 'platform') {
@@ -2598,7 +1837,7 @@ class MarioEducational extends Module {
 
         // Explosion effect
         this._addParticles(boulder.x + boulder.width/2, boulder.y + boulder.height/2, '#FF4500');
-        this._playSound('enemy_defeat');
+        soundSystem.play('enemy_defeat');
 
         // Kill enemies in explosion radius (50 pixels)
         this._enemies.forEach((enemy, enemyIndex) => {
@@ -2621,7 +1860,7 @@ class MarioEducational extends Module {
         if (marioDistance < 50) {
             console.log(`💀 Mario killed by boulder explosion! Respawning at level start. Distance: ${marioDistance.toFixed(0)}`);
             this._addParticles(this._mario.x, this._mario.y, '#FF0000'); // Red death particles
-            this._playSound('enemy_defeat');
+            soundSystem.play('enemy_defeat');
 
             // Reset Mario to start position like other enemy deaths
             const level = this._levelData[this._currentLevelIndex];
@@ -2640,69 +1879,12 @@ class MarioEducational extends Module {
     }
 
     _updateStones() {
-        this._stones.forEach((stone, index) => {
-            // Apply gravity and movement (similar to boulders but simpler)
-            stone.velocityY += 0.015; // Slightly more gravity than boulders
-            stone.x += stone.velocityX;
-            stone.y += stone.velocityY;
-
-            // Check ground collision
-            const groundLevel = this._config.canvasHeight - 50;
-            if (stone.y + stone.height >= groundLevel) {
-                // Stone hits ground - create small particle effect and disappear
-                this._addParticles(stone.x + stone.width/2, stone.y + stone.height/2, '#A0522D');
-                this._stones.splice(index, 1);
-                return;
+        this._stones = Catapult.updateStones(
+            this._stones, this._mario, this._platforms,
+            (stone, idx, type) => {
+                if (type === 'mario') this._restartLevel();
             }
-
-            // Check collision with Mario (stones kill Mario!)
-            if (this._isColliding(stone, this._mario)) {
-                console.log(`🪨 Stone hit Mario! Respawning at level start.`);
-                this._addParticles(this._mario.x, this._mario.y, '#FF0000'); // Red death particles
-                this._playSound('enemy_defeat');
-
-                // Reset Mario to start position like other deaths
-                const level = this._levelData[this._currentLevelIndex];
-                this._mario.x = level.startX;
-                this._mario.y = level.startY;
-                this._mario.velocityX = 0;
-                this._mario.velocityY = 0;
-
-                // Remove the stone that hit Mario
-                this._stones.splice(index, 1);
-                return;
-            }
-
-            // Check collision with platforms/walls (stones disappear on impact)
-            let hasHit = false;
-
-            // Check platforms
-            this._platforms.forEach((platform) => {
-                if (!hasHit && this._isColliding(stone, platform)) {
-                    this._addParticles(stone.x + stone.width/2, stone.y + stone.height/2, '#A0522D');
-                    this._stones.splice(index, 1);
-                    hasHit = true;
-                    return;
-                }
-            });
-
-            // Check walls
-            if (!hasHit) {
-                this._walls.forEach((wall) => {
-                    if (!hasHit && this._isColliding(stone, wall)) {
-                        this._addParticles(stone.x + stone.width/2, stone.y + stone.height/2, '#A0522D');
-                        this._stones.splice(index, 1);
-                        hasHit = true;
-                        return;
-                    }
-                });
-            }
-
-            // Remove stones that go off-screen
-            if (stone.x < -100 || stone.x > this._levelWidth + 100 || stone.y > this._config.canvasHeight + 100) {
-                this._stones.splice(index, 1);
-            }
-        });
+        );
     }
 
     _renderStones() {
@@ -2794,7 +1976,7 @@ class MarioEducational extends Module {
 
         // Create star animation particles
         this._createFinishLineStars();
-        this._playSound('finish_stars');
+        soundSystem.play('finish_stars');
 
         // Complete level after animation
         setTimeout(() => {
@@ -2882,11 +2064,11 @@ class MarioEducational extends Module {
                 }
 
                 // Play sound effects for each wave
-                this._playSound('finish_stars');
+                soundSystem.play('finish_stars');
 
                 // Extra sound effect for bigger waves
                 if (wave >= 4) {
-                    setTimeout(() => this._playSound('powerup'), 100);
+                    setTimeout(() => soundSystem.play('powerup'), 100);
                 }
             }, wave * 200); // Faster succession
         }
@@ -2909,7 +2091,7 @@ class MarioEducational extends Module {
                     isEpicFinalStar: true
                 });
             }
-            this._playSound('level_complete');
+            soundSystem.play('level_complete');
             console.log('🌟💥🎆 MEGA BONUS EXPLOSION! 300 GIANT STARS! 🎆💥🌟');
         }, 2000);
 
@@ -2921,7 +2103,7 @@ class MarioEducational extends Module {
         this._isCelebrating = true; // Block enemies but allow animations
 
         // Play level complete sound
-        this._playSound('level_complete');
+        soundSystem.play('level_complete');
 
         // Add star animations for every level completion
         this._createLevelCompleteStars();
@@ -3066,837 +2248,39 @@ class MarioEducational extends Module {
         // Subtract score penalty for death
         const penalty = 250;
         this._score = Math.max(0, this._score - penalty);
-        this._playSound('death');
+        soundSystem.play('death');
         console.log(`💀 Mario died! Score penalty: -${penalty}. New score: ${this._score}`);
     }
 
     _render() {
-        // Clear canvas
-        this._ctx.clearRect(0, 0, this._config.canvasWidth, this._config.canvasHeight);
+        // Build game state object for renderer
+        const gameState = {
+            mario: this._mario,
+            camera: this._camera,
+            platforms: this._platforms,
+            questionBlocks: this._questionBlocks,
+            enemies: this._enemies,
+            walls: this._walls,
+            piranhaPlants: this._piranhaPlants,
+            projectiles: this._projectiles,
+            catapults: this._catapults,
+            boulders: this._boulders,
+            stones: this._stones,
+            flyingEyes: this._flyingEyes,
+            boss: this._boss,
+            castle: this._castle,
+            finishLine: this._finishLine,
+            particles: this._particles,
+            currentLevel: this._currentLevel,
+            lives: this._lives,
+            score: this._score,
+            debugMode: false // Can be toggled
+        };
 
-        // Render background
-        this._renderBackground();
-
-        // Save context for camera translation
-        this._ctx.save();
-        this._ctx.translate(-this._camera.x, -this._camera.y);
-
-        // Render platforms
-        this._renderPlatforms();
-
-        // Render question blocks
-        this._renderQuestionBlocks();
-
-        // Render enemies
-        this._renderEnemies();
-
-        // Render walls
-        this._renderWalls();
-
-        // Render advanced level elements
-        this._renderPiranhaPlants();
-        this._renderProjectiles();
-
-        // Render level 4+ elements
-        this._renderCatapults();
-        this._renderBoulders();
-        this._renderStones();
-
-        // Render level 5+ elements
-        this._renderFlyingEyes();
-
-        // Render level 6 boss elements
-        this._renderBoss();
-
-        // Render castle (visual only)
-        this._renderCastle();
-
-        // Render finish line
-        this._renderFinishLine();
-
-        // Render Mario
-        this._renderMario();
-
-        // Render particles
-        this._renderParticles();
-
-        // Render debug hitboxes if needed
-        this._renderDebugHitboxes();
-
-        // Restore context
-        this._ctx.restore();
-
-        // Render UI
-        this._renderUI();
+        // Delegate rendering to helper
+        renderer.render(this._ctx, gameState, this._config);
     }
 
-    _renderBackground() {
-        // Sky gradient
-        const gradient = this._ctx.createLinearGradient(0, 0, 0, this._config.canvasHeight);
-        gradient.addColorStop(0, '#87CEEB');
-        gradient.addColorStop(1, '#98FB98');
-        this._ctx.fillStyle = gradient;
-        this._ctx.fillRect(0, 0, this._config.canvasWidth, this._config.canvasHeight);
-
-        // Clouds (fixed position, don't scroll with camera)
-        this._ctx.fillStyle = 'rgba(255, 255, 255, 0.8)';
-        for (let i = 0; i < 5; i++) {
-            const x = (i * 300 + 100 - this._camera.x * 0.3) % (this._config.canvasWidth + 200);
-            const y = 80 + i * 30;
-            this._renderCloud(x, y);
-        }
-    }
-
-    _renderCloud(x, y) {
-        this._ctx.beginPath();
-        this._ctx.arc(x, y, 30, 0, Math.PI * 2);
-        this._ctx.arc(x + 30, y, 40, 0, Math.PI * 2);
-        this._ctx.arc(x + 60, y, 30, 0, Math.PI * 2);
-        this._ctx.fill();
-    }
-
-    _renderPlatforms() {
-        this._platforms.forEach(platform => {
-            this._ctx.fillStyle = platform.color;
-            this._ctx.fillRect(platform.x, platform.y, platform.width, platform.height);
-
-            // Add outline
-            this._ctx.strokeStyle = '#000';
-            this._ctx.lineWidth = 2;
-            this._ctx.strokeRect(platform.x, platform.y, platform.width, platform.height);
-        });
-    }
-
-    _renderQuestionBlocks() {
-        this._questionBlocks.forEach(block => {
-            // Block
-            this._ctx.fillStyle = block.color;
-            this._ctx.fillRect(block.x, block.y, block.width, block.height);
-
-            // Outline
-            this._ctx.strokeStyle = '#000';
-            this._ctx.lineWidth = 2;
-            this._ctx.strokeRect(block.x, block.y, block.width, block.height);
-
-            // Symbol
-            this._ctx.fillStyle = '#000';
-            this._ctx.font = 'bold 24px Arial';
-            this._ctx.textAlign = 'center';
-            this._ctx.textBaseline = 'middle';
-            this._ctx.fillText(
-                block.symbol,
-                block.x + block.width / 2,
-                block.y + block.height / 2
-            );
-        });
-    }
-
-    _renderEnemies() {
-        this._enemies.forEach(enemy => {
-            this._ctx.fillStyle = enemy.color;
-            this._ctx.fillRect(enemy.x, enemy.y, enemy.width, enemy.height);
-
-            // Simple face
-            this._ctx.fillStyle = '#FFF';
-            this._ctx.fillRect(enemy.x + 3, enemy.y + 3, 3, 3); // Eye
-            this._ctx.fillRect(enemy.x + 14, enemy.y + 3, 3, 3); // Eye
-
-            // Draw helmet for protected enemies
-            if (enemy.hasHelmet) {
-                this._ctx.fillStyle = '#C0C0C0'; // Silver helmet
-                this._ctx.fillRect(enemy.x - 1, enemy.y - 4, enemy.width + 2, 6);
-
-                // Helmet shine
-                this._ctx.fillStyle = '#E8E8E8';
-                this._ctx.fillRect(enemy.x + 2, enemy.y - 3, 4, 2);
-
-                // Helmet symbol (shield)
-                this._ctx.fillStyle = '#FFD700';
-                this._ctx.fillRect(enemy.x + 8, enemy.y - 2, 4, 2);
-            }
-        });
-    }
-
-    _renderWalls() {
-        this._walls.forEach(wall => {
-            // Wall main body
-            this._ctx.fillStyle = wall.color;
-            this._ctx.fillRect(wall.x, wall.y, wall.width, wall.height);
-
-            // Add brick pattern for visual appeal
-            this._ctx.strokeStyle = '#654321'; // Darker brown for lines
-            this._ctx.lineWidth = 1;
-
-            // Horizontal lines
-            for (let y = wall.y + 20; y < wall.y + wall.height; y += 20) {
-                this._ctx.beginPath();
-                this._ctx.moveTo(wall.x, y);
-                this._ctx.lineTo(wall.x + wall.width, y);
-                this._ctx.stroke();
-            }
-
-            // Vertical lines (offset every other row)
-            for (let row = 0; row < Math.floor(wall.height / 20); row++) {
-                const yPos = wall.y + row * 20;
-                const offset = (row % 2) * 10; // Offset every other row
-
-                for (let x = wall.x + offset + 20; x < wall.x + wall.width; x += 20) {
-                    this._ctx.beginPath();
-                    this._ctx.moveTo(x, yPos);
-                    this._ctx.lineTo(x, Math.min(yPos + 20, wall.y + wall.height));
-                    this._ctx.stroke();
-                }
-            }
-
-            // Wall type indicator (for debugging)
-            if (wall.type === 'tall') {
-                this._ctx.fillStyle = '#FF0000';
-                this._ctx.fillRect(wall.x + wall.width - 5, wall.y, 5, 20);
-            }
-        });
-    }
-
-
-    _renderPiranhaPlants() {
-        this._piranhaPlants.forEach(plant => {
-            if (plant.flattened) {
-                // Flattened plant - just a green pancake on the ground
-                this._ctx.fillStyle = '#556B2F'; // Dark olive green (dead/flat)
-                this._ctx.fillRect(plant.x, plant.y + plant.height - 5, plant.width, 5);
-
-                // Some scattered debris
-                this._ctx.fillStyle = '#8B4513'; // Brown debris
-                this._ctx.fillRect(plant.x + 5, plant.y + plant.height - 3, 3, 2);
-                this._ctx.fillRect(plant.x + 20, plant.y + plant.height - 4, 2, 3);
-                this._ctx.fillRect(plant.x + 12, plant.y + plant.height - 2, 4, 1);
-            } else {
-                // Normal living plant
-                // Plant stem
-                this._ctx.fillStyle = '#228B22'; // Forest green
-                this._ctx.fillRect(plant.x + 10, plant.y, 10, plant.height);
-
-                // Plant head (circular)
-                this._ctx.fillStyle = '#32CD32'; // Lime green
-                this._ctx.beginPath();
-                this._ctx.arc(plant.x + 15, plant.y + 10, 12, 0, Math.PI * 2);
-                this._ctx.fill();
-
-                // Sharp teeth
-                this._ctx.fillStyle = '#FFFFFF';
-                for (let i = 0; i < 6; i++) {
-                    const angle = (i * Math.PI * 2) / 6;
-                    const toothX = plant.x + 15 + Math.cos(angle) * 8;
-                    const toothY = plant.y + 10 + Math.sin(angle) * 8;
-                    this._ctx.fillRect(toothX - 1, toothY - 1, 2, 4);
-                }
-
-                // Red mouth center
-                this._ctx.fillStyle = '#DC143C'; // Crimson
-                this._ctx.beginPath();
-                this._ctx.arc(plant.x + 15, plant.y + 10, 6, 0, Math.PI * 2);
-                this._ctx.fill();
-
-                // Eyes
-                this._ctx.fillStyle = '#000000';
-                this._ctx.fillRect(plant.x + 10, plant.y + 5, 3, 3);
-                this._ctx.fillRect(plant.x + 17, plant.y + 5, 3, 3);
-            }
-        });
-    }
-
-    _renderProjectiles() {
-        this._projectiles.forEach(projectile => {
-            // Fireball effect
-            this._ctx.fillStyle = projectile.color;
-            this._ctx.beginPath();
-            this._ctx.arc(projectile.x + projectile.width/2, projectile.y + projectile.height/2, projectile.width/2, 0, Math.PI * 2);
-            this._ctx.fill();
-
-            // Inner glow
-            this._ctx.fillStyle = '#FFFF00'; // Yellow center
-            this._ctx.beginPath();
-            this._ctx.arc(projectile.x + projectile.width/2, projectile.y + projectile.height/2, projectile.width/4, 0, Math.PI * 2);
-            this._ctx.fill();
-        });
-    }
-
-    _renderCatapults() {
-        this._catapults.forEach(catapult => {
-            // Catapult base
-            this._ctx.fillStyle = catapult.color;
-            this._ctx.fillRect(catapult.x, catapult.y + 40, catapult.width, 40);
-
-            // Catapult arm
-            this._ctx.fillStyle = '#654321'; // Dark brown
-            this._ctx.fillRect(catapult.x + 10, catapult.y, 8, 50);
-
-            // Bucket
-            this._ctx.fillStyle = '#8B4513';
-            this._ctx.fillRect(catapult.x + 5, catapult.y, 18, 12);
-
-            // Support beams
-            this._ctx.strokeStyle = '#654321';
-            this._ctx.lineWidth = 3;
-            this._ctx.beginPath();
-            this._ctx.moveTo(catapult.x + 30, catapult.y + 40);
-            this._ctx.lineTo(catapult.x + 14, catapult.y + 25);
-            this._ctx.stroke();
-        });
-    }
-
-    _renderBoulders() {
-        this._boulders.forEach(boulder => {
-            // Boulder body
-            this._ctx.fillStyle = boulder.color;
-            this._ctx.beginPath();
-            this._ctx.arc(boulder.x + boulder.width/2, boulder.y + boulder.height/2, boulder.width/2, 0, Math.PI * 2);
-            this._ctx.fill();
-
-            // Boulder texture/cracks
-            this._ctx.strokeStyle = '#555555';
-            this._ctx.lineWidth = 1;
-            this._ctx.beginPath();
-            this._ctx.arc(boulder.x + boulder.width/2 - 5, boulder.y + boulder.height/2 - 3, 3, 0, Math.PI);
-            this._ctx.stroke();
-            this._ctx.beginPath();
-            this._ctx.arc(boulder.x + boulder.width/2 + 4, boulder.y + boulder.height/2 + 2, 2, 0, Math.PI);
-            this._ctx.stroke();
-
-            // Show trajectory line for flying boulders (debug)
-            if (!boulder.hasLanded && boulder.velocityX !== 0) {
-                this._ctx.strokeStyle = 'rgba(255, 255, 255, 0.3)';
-                this._ctx.lineWidth = 1;
-                this._ctx.setLineDash([5, 5]);
-                this._ctx.beginPath();
-                this._ctx.moveTo(boulder.x + boulder.width/2, boulder.y + boulder.height/2);
-                this._ctx.lineTo(boulder.x + boulder.velocityX * 10, boulder.y + boulder.velocityY * 10);
-                this._ctx.stroke();
-                this._ctx.setLineDash([]);
-            }
-        });
-    }
-
-    _renderFinishLine() {
-        const level = this._levelData[this._currentLevelIndex];
-        const finishX = level.endX;
-
-        // Draw checkered flag pattern
-        this._ctx.fillStyle = '#FFD700'; // Gold color
-        this._ctx.fillRect(finishX - 5, 50, 10, this._config.canvasHeight - 100);
-
-        // Add black and white checkered pattern
-        const squareSize = 20;
-        for (let y = 50; y < this._config.canvasHeight - 50; y += squareSize) {
-            for (let x = 0; x < 10; x += squareSize / 2) {
-                const isBlack = Math.floor((y - 50) / squareSize) % 2 === Math.floor(x / (squareSize / 2)) % 2;
-                this._ctx.fillStyle = isBlack ? '#000000' : '#FFFFFF';
-                this._ctx.fillRect(finishX - 5 + x, y, squareSize / 2, squareSize);
-            }
-        }
-
-        // Add "FINISH" text
-        this._ctx.save();
-        this._ctx.translate(finishX, 30);
-        this._ctx.rotate(-Math.PI / 2);
-        this._ctx.fillStyle = '#FF0000';
-        this._ctx.font = 'bold 16px Arial';
-        this._ctx.textAlign = 'center';
-        this._ctx.fillText('FINISH', 0, 0);
-        this._ctx.restore();
-
-        // Add arrow pointing to finish
-        if (this._mario.x < finishX - 200) {
-            this._ctx.fillStyle = '#FFD700';
-            this._ctx.font = 'bold 20px Arial';
-            this._ctx.textAlign = 'left';
-            this._ctx.fillText('→ FINISH', finishX - 150, 25);
-        }
-    }
-
-    _updateFlyingEyes() {
-        const currentTime = Date.now();
-
-        this._flyingEyes.forEach((eye, index) => {
-            // Calculate distance to Mario
-            const distanceToMario = Math.sqrt(
-                Math.pow(eye.x - this._mario.x, 2) +
-                Math.pow(eye.y - this._mario.y, 2)
-            );
-
-            // Determine if eye should chase Mario
-            eye.isChasing = distanceToMario < eye.chaseDistance;
-
-            // Handle dash behavior
-            if (eye.isDashing) {
-                eye.dashDuration--;
-                if (eye.dashDuration <= 0) {
-                    eye.isDashing = false;
-                    eye.lastDashTime = currentTime;
-                    console.log(`👁️ Eye finished dashing!`);
-                }
-                // During dash, maintain dash velocity (no other movement changes)
-            } else {
-                // Check if it's time to dash (only when chasing)
-                if (eye.isChasing && currentTime - eye.lastDashTime > eye.dashInterval && Math.random() < 0.3) {
-                    // Start dash in random 90-degree direction
-                    const dashDirections = [
-                        { x: 1, y: 0 },   // Right
-                        { x: -1, y: 0 },  // Left
-                        { x: 0, y: 1 },   // Down
-                        { x: 0, y: -1 }   // Up
-                    ];
-                    const dashDir = dashDirections[Math.floor(Math.random() * 4)];
-
-                    eye.velocityX = dashDir.x * eye.dashSpeed;
-                    eye.velocityY = dashDir.y * eye.dashSpeed;
-                    eye.isDashing = true;
-                    eye.dashDuration = 20; // Dash for 20 frames (~0.33 seconds)
-                    console.log(`👁️ Eye started dashing! Direction: ${dashDir.x}, ${dashDir.y}`);
-                } else if (eye.isChasing) {
-                    // Normal chase behavior - move toward Mario
-                    const deltaX = this._mario.x - eye.x;
-                    const deltaY = this._mario.y - eye.y;
-                    const distance = Math.sqrt(deltaX * deltaX + deltaY * deltaY);
-
-                    if (distance > 0) {
-                        // Normalize direction and apply chase speed
-                        eye.velocityX = (deltaX / distance) * eye.chaseSpeed;
-                        eye.velocityY = (deltaY / distance) * eye.chaseSpeed;
-                    }
-
-                    console.log(`👁️ Eye chasing Mario! Distance: ${distanceToMario.toFixed(0)}`);
-                } else {
-                    // Idle behavior - random floating movement (faster now)
-                    if (currentTime - eye.lastDirectionChange > eye.directionChangeInterval) {
-                        // Change direction randomly
-                        eye.velocityX = (Math.random() - 0.5) * eye.idleSpeed * 2;
-                        eye.velocityY = (Math.random() - 0.5) * eye.idleSpeed * 2;
-                        eye.lastDirectionChange = currentTime;
-                        eye.directionChangeInterval = 2000 + Math.random() * 3000;
-                    }
-                }
-            }
-
-            // Apply movement
-            eye.x += eye.velocityX;
-            eye.y += eye.velocityY;
-
-            // Keep eyes within screen bounds
-            if (eye.x < 0) {
-                eye.x = 0;
-                eye.velocityX = Math.abs(eye.velocityX);
-            } else if (eye.x > this._levelWidth - eye.width) {
-                eye.x = this._levelWidth - eye.width;
-                eye.velocityX = -Math.abs(eye.velocityX);
-            }
-
-            if (eye.y < 0) {
-                eye.y = 0;
-                eye.velocityY = Math.abs(eye.velocityY);
-            } else if (eye.y > this._config.canvasHeight - eye.height - 50) { // Stay above ground
-                eye.y = this._config.canvasHeight - eye.height - 50;
-                eye.velocityY = -Math.abs(eye.velocityY);
-            }
-
-            // Blinking animation
-            eye.blinkTimer++;
-            if (eye.blinkTimer > 120 + Math.random() * 180) { // Blink every 2-5 seconds
-                eye.isBlinking = true;
-                eye.blinkTimer = 0;
-            }
-            if (eye.isBlinking && eye.blinkTimer > 10) { // Blink lasts 10 frames
-                eye.isBlinking = false;
-            }
-
-            // Check collision with Mario
-            if (this._isColliding(this._mario, eye)) {
-                // Eye can be stomped like normal enemies
-                const overlapTop = (this._mario.y + this._mario.height) - eye.y;
-                const overlapBottom = (eye.y + eye.height) - this._mario.y;
-
-                if (this._mario.velocityY > 0 && overlapTop < overlapBottom) {
-                    // Mario stomped the eye
-                    this._flyingEyes.splice(index, 1);
-                    this._mario.velocityY = this._config.jumpForce / 2; // Small bounce
-                    this._addParticles(eye.x, eye.y, '#DC143C'); // Red particles
-                    this._playSound('enemy_defeat');
-                    console.log(`👁️ Mario stomped flying eye!`);
-                } else {
-                    // Eye hurts Mario - reset level
-                    console.log(`💥 Mario hit by flying eye - restarting level`);
-                    this._restartLevel();
-                }
-            }
-        });
-    }
-
-    _renderFlyingEyes() {
-        this._flyingEyes.forEach(eye => {
-            // Draw eye body (white oval)
-            this._ctx.fillStyle = '#FFFFFF';
-            this._ctx.beginPath();
-            this._ctx.ellipse(eye.x + eye.width/2, eye.y + eye.height/2, eye.width/2, eye.height/2, 0, 0, 2 * Math.PI);
-            this._ctx.fill();
-
-            if (!eye.isBlinking) {
-                // Draw red iris
-                this._ctx.fillStyle = eye.color;
-                this._ctx.beginPath();
-                this._ctx.ellipse(eye.x + eye.width/2, eye.y + eye.height/2, eye.width/3, eye.height/3, 0, 0, 2 * Math.PI);
-                this._ctx.fill();
-
-                // Draw black pupil that follows Mario
-                const deltaX = this._mario.x - eye.x;
-                const deltaY = this._mario.y - eye.y;
-                const distance = Math.sqrt(deltaX * deltaX + deltaY * deltaY);
-
-                let pupilOffsetX = 0;
-                let pupilOffsetY = 0;
-
-                if (distance > 0) {
-                    const maxOffset = 4; // Maximum pupil movement
-                    pupilOffsetX = (deltaX / distance) * maxOffset;
-                    pupilOffsetY = (deltaY / distance) * maxOffset;
-                }
-
-                this._ctx.fillStyle = eye.pupilColor;
-                this._ctx.beginPath();
-                this._ctx.arc(
-                    eye.x + eye.width/2 + pupilOffsetX,
-                    eye.y + eye.height/2 + pupilOffsetY,
-                    eye.width/6,
-                    0,
-                    2 * Math.PI
-                );
-                this._ctx.fill();
-            } else {
-                // Draw closed eye (horizontal line)
-                this._ctx.strokeStyle = '#000000';
-                this._ctx.lineWidth = 2;
-                this._ctx.beginPath();
-                this._ctx.moveTo(eye.x + 5, eye.y + eye.height/2);
-                this._ctx.lineTo(eye.x + eye.width - 5, eye.y + eye.height/2);
-                this._ctx.stroke();
-            }
-
-            // Add subtle outline
-            this._ctx.strokeStyle = '#CCCCCC';
-            this._ctx.lineWidth = 1;
-            this._ctx.beginPath();
-            this._ctx.ellipse(eye.x + eye.width/2, eye.y + eye.height/2, eye.width/2, eye.height/2, 0, 0, 2 * Math.PI);
-            this._ctx.stroke();
-        });
-    }
-
-    _updateBoss() {
-        if (!this._boss) return;
-
-        const currentTime = Date.now();
-
-        // Update boss collision cooldown
-        if (this._bossCollisionCooldown > 0) {
-            this._bossCollisionCooldown--;
-        }
-
-        // Update damage flash timer
-        if (this._boss.damageFlashTimer > 0) {
-            this._boss.damageFlashTimer--;
-            if (this._boss.damageFlashTimer <= 0) {
-                this._boss.isDamaged = false;
-            }
-        }
-
-        // Boss collision with Mario (blocks the path) - with cooldown to prevent loop
-        if (this._isColliding(this._mario, this._boss) && this._bossCollisionCooldown <= 0) {
-            console.log(`👹 Mario hit boss body - bounced back!`);
-
-            // TRUE velocity inversion: velocity = velocity * -1
-            this._mario.velocityX = this._mario.velocityX * -1 - 3; // Invert + add knockback
-            this._mario.velocityY = this._config.jumpForce * 0.7; // Bounce upward
-
-            // Set collision cooldown (3 ticks)
-            this._bossCollisionCooldown = 3;
-
-            // Impact particles
-            this._addParticles(
-                this._mario.x + this._mario.width / 2,
-                this._mario.y + this._mario.height / 2,
-                '#FFFF00' // Yellow impact particles
-            );
-
-            // Impact sound
-            this._playSound('enemy_defeat');
-
-            console.log(`⏱️ Boss collision cooldown set: ${this._bossCollisionCooldown} ticks`);
-        }
-    }
-
-    _renderBoss() {
-        if (!this._boss) return;
-
-        const ctx = this._ctx;
-        const x = this._boss.x;
-        const y = this._boss.y;
-        const w = this._boss.width;
-        const h = this._boss.height;
-
-        // Boss main body (torso) - more humanoid proportions
-        ctx.fillStyle = this._boss.isDamaged ? '#FF6666' : this._boss.color;
-        ctx.fillRect(x + 20, y, w - 40, h * 0.6); // Torso
-
-        // Boss legs (separated)
-        ctx.fillRect(x + 10, y + h * 0.6, 35, h * 0.4); // Left leg
-        ctx.fillRect(x + w - 45, y + h * 0.6, 35, h * 0.4); // Right leg
-
-        // Boss head (bigger and more menacing)
-        const headWidth = 60;
-        const headHeight = 50;
-        ctx.fillRect(x + (w - headWidth) / 2, y - headHeight, headWidth, headHeight);
-
-        // Boss outline for all parts
-        ctx.strokeStyle = '#000000';
-        ctx.lineWidth = 3;
-        ctx.strokeRect(x + 20, y, w - 40, h * 0.6); // Torso outline
-        ctx.strokeRect(x + 10, y + h * 0.6, 35, h * 0.4); // Left leg outline
-        ctx.strokeRect(x + w - 45, y + h * 0.6, 35, h * 0.4); // Right leg outline
-        ctx.strokeRect(x + (w - headWidth) / 2, y - headHeight, headWidth, headHeight); // Head outline
-
-        // Boss eyes (glowing red, larger)
-        ctx.fillStyle = this._boss.eyeColor;
-        const eyeSize = 12;
-        ctx.fillRect(x + (w - headWidth) / 2 + 10, y - headHeight + 15, eyeSize, eyeSize); // Left eye
-        ctx.fillRect(x + (w - headWidth) / 2 + headWidth - 22, y - headHeight + 15, eyeSize, eyeSize); // Right eye
-
-        // Boss mouth (menacing)
-        ctx.fillStyle = '#000000';
-        ctx.fillRect(x + (w - headWidth) / 2 + 15, y - headHeight + 35, headWidth - 30, 8);
-
-        // Shoulder spikes for more intimidating look
-        ctx.fillStyle = '#8B4513';
-        ctx.fillRect(x + 15, y + 5, 15, 25); // Left shoulder
-        ctx.fillRect(x + w - 30, y + 5, 15, 25); // Right shoulder
-
-        // Boss knees (damage zones) - integrated styling as kneepads
-        ctx.fillStyle = '#FFD700'; // Gold kneepads
-        ctx.fillRect(
-            this._boss.leftKnee.x + 5,
-            this._boss.leftKnee.y + 5,
-            this._boss.leftKnee.width - 10,
-            this._boss.leftKnee.height - 10
-        );
-        ctx.fillRect(
-            this._boss.rightKnee.x + 5,
-            this._boss.rightKnee.y + 5,
-            this._boss.rightKnee.width - 10,
-            this._boss.rightKnee.height - 10
-        );
-
-        // Kneepad outlines
-        ctx.strokeStyle = '#B8860B'; // Dark goldenrod outline
-        ctx.lineWidth = 2;
-        ctx.strokeRect(
-            this._boss.leftKnee.x + 5,
-            this._boss.leftKnee.y + 5,
-            this._boss.leftKnee.width - 10,
-            this._boss.leftKnee.height - 10
-        );
-        ctx.strokeRect(
-            this._boss.rightKnee.x + 5,
-            this._boss.rightKnee.y + 5,
-            this._boss.rightKnee.width - 10,
-            this._boss.rightKnee.height - 10
-        );
-
-        // Boss health bar
-        const healthBarWidth = 200;
-        const healthBarHeight = 20;
-        const healthBarX = this._boss.x + (this._boss.width / 2) - (healthBarWidth / 2);
-        const healthBarY = this._boss.y - 40;
-
-        // Health bar background
-        ctx.fillStyle = '#FF0000';
-        ctx.fillRect(healthBarX, healthBarY, healthBarWidth, healthBarHeight);
-
-        // Health bar foreground
-        const healthPercent = this._boss.health / this._boss.maxHealth;
-        ctx.fillStyle = '#00FF00';
-        ctx.fillRect(healthBarX, healthBarY, healthBarWidth * healthPercent, healthBarHeight);
-
-        // Health bar border
-        ctx.strokeStyle = '#000000';
-        ctx.lineWidth = 2;
-        ctx.strokeRect(healthBarX, healthBarY, healthBarWidth, healthBarHeight);
-
-        // Render turrets on boss
-        this._bossTurrets.forEach(turret => {
-            ctx.fillStyle = turret.color;
-            ctx.fillRect(turret.x, turret.y, turret.width, turret.height);
-            ctx.strokeStyle = '#000000';
-            ctx.lineWidth = 1;
-            ctx.strokeRect(turret.x, turret.y, turret.width, turret.height);
-        });
-    }
-
-    _renderMario() {
-        // Mario body
-        this._ctx.fillStyle = this._mario.color;
-        this._ctx.fillRect(this._mario.x, this._mario.y, this._mario.width, this._mario.height);
-
-        // Hat
-        this._ctx.fillStyle = '#8B0000';
-        this._ctx.fillRect(this._mario.x + 4, this._mario.y - 8, this._mario.width - 8, 12);
-
-        // Face
-        this._ctx.fillStyle = '#FFDBAC';
-        this._ctx.fillRect(this._mario.x + 8, this._mario.y + 8, 16, 16);
-
-        // Eyes
-        this._ctx.fillStyle = '#000';
-        const eyeOffset = this._mario.facing === 'right' ? 2 : -2;
-        this._ctx.fillRect(this._mario.x + 10 + eyeOffset, this._mario.y + 12, 2, 2);
-        this._ctx.fillRect(this._mario.x + 18 + eyeOffset, this._mario.y + 12, 2, 2);
-
-        // Mustache
-        this._ctx.fillRect(this._mario.x + 12, this._mario.y + 18, 8, 2);
-    }
-
-    _renderParticles() {
-        this._particles.forEach(particle => {
-            const alpha = particle.life / particle.maxLife;
-
-            if (particle.isFinishStar) {
-                // Render finish line stars as actual star symbols
-                this._ctx.font = `${particle.size}px serif`;
-                this._ctx.textAlign = 'center';
-                this._ctx.textBaseline = 'middle';
-                this._ctx.fillStyle = particle.color + Math.floor(alpha * 255).toString(16).padStart(2, '0');
-                this._ctx.fillText('⭐', particle.x, particle.y);
-            } else {
-                // Regular particles
-                this._ctx.fillStyle = particle.color + Math.floor(alpha * 255).toString(16).padStart(2, '0');
-                this._ctx.fillRect(particle.x, particle.y, 4, 4);
-            }
-        });
-
-        // Reset text alignment
-        this._ctx.textAlign = 'left';
-        this._ctx.textBaseline = 'top';
-    }
-
-    _renderCastle() {
-        if (!this._castleStructure) return;
-
-        const castle = this._castleStructure;
-
-        // Set font for castle emoji
-        this._ctx.font = `${castle.size}px serif`;
-        this._ctx.textAlign = 'center';
-        this._ctx.textBaseline = 'middle';
-
-        // Render castle emoji
-        this._ctx.fillText(castle.emoji, castle.x, castle.y);
-
-        // Render princess in the castle
-        if (castle.princess) {
-            this._ctx.font = `${castle.princess.size}px serif`;
-            this._ctx.fillText(castle.princess.emoji, castle.princess.x, castle.princess.y);
-        }
-
-        // Add sparkles around the massive castle (360px)
-        this._ctx.font = '40px serif';
-        this._ctx.fillText('✨', castle.x - 180, castle.y - 120);
-        this._ctx.fillText('✨', castle.x + 180, castle.y - 120);
-        this._ctx.fillText('✨', castle.x - 120, castle.y + 120);
-        this._ctx.fillText('✨', castle.x + 120, castle.y + 120);
-
-        // Additional sparkles for the massive castle
-        this._ctx.font = '30px serif';
-        this._ctx.fillText('✨', castle.x - 220, castle.y);
-        this._ctx.fillText('✨', castle.x + 220, castle.y);
-        this._ctx.fillText('✨', castle.x, castle.y - 200);
-        this._ctx.fillText('✨', castle.x, castle.y + 180);
-
-        // Extra sparkles for grandeur
-        this._ctx.font = '25px serif';
-        this._ctx.fillText('⭐', castle.x - 160, castle.y - 60);
-        this._ctx.fillText('⭐', castle.x + 160, castle.y - 60);
-        this._ctx.fillText('⭐', castle.x - 60, castle.y + 160);
-        this._ctx.fillText('⭐', castle.x + 60, castle.y + 160);
-
-        // Reset text alignment
-        this._ctx.textAlign = 'left';
-        this._ctx.textBaseline = 'top';
-    }
-
-    _renderUI() {
-        if (this._uiOverlay) {
-            this._uiOverlay.innerHTML = `
-                <div>Score: ${this._score}</div>
-                <div>Level: ${this._currentLevel}/${this._config.maxLevels}</div>
-                <div>Questions: ${this._questionsAnswered}</div>
-                <div style="margin-top: 10px; font-size: 14px;">
-                    Use Arrow Keys or WASD to move, Space/Up to jump
-                </div>
-            `;
-        }
-    }
-
-    _getRandomSentence() {
-        const availableSentences = this._sentences.filter(s => !this._usedSentences.includes(s));
-        if (availableSentences.length === 0) {
-            // Reset used sentences if all are used
-            this._usedSentences = [];
-            return this._sentences[0];
-        }
-
-        const sentence = availableSentences[Math.floor(Math.random() * availableSentences.length)];
-        this._usedSentences.push(sentence);
-        return sentence;
-    }
-
-    _shuffleArray(array) {
-        const shuffled = [...array];
-        for (let i = shuffled.length - 1; i > 0; i--) {
-            const j = Math.floor(Math.random() * (i + 1));
-            [shuffled[i], shuffled[j]] = [shuffled[j], shuffled[i]];
-        }
-        return shuffled;
-    }
-
-    _renderDebugHitboxes() {
-        // Only render in debug mode (can be toggled)
-        if (!window.DEBUG_HITBOXES) return;
-
-        this._ctx.strokeStyle = '#FF0000';
-        this._ctx.lineWidth = 2;
-
-        // Mario hitbox
-        this._ctx.strokeRect(this._mario.x, this._mario.y, this._mario.width, this._mario.height);
-
-        // Platform hitboxes
-        this._ctx.strokeStyle = '#00FF00';
-        this._platforms.forEach(platform => {
-            this._ctx.strokeRect(platform.x, platform.y, platform.width, platform.height);
-        });
-
-        // Wall hitboxes
-        this._ctx.strokeStyle = '#8B4513';
-        this._walls.forEach(wall => {
-            this._ctx.strokeRect(wall.x, wall.y, wall.width, wall.height);
-        });
-
-        // Enemy hitboxes
-        this._ctx.strokeStyle = '#FF00FF';
-        this._enemies.forEach(enemy => {
-            this._ctx.strokeRect(enemy.x, enemy.y, enemy.width, enemy.height);
-        });
-
-        // Question block hitboxes
-        this._ctx.strokeStyle = '#FFFF00';
-        this._questionBlocks.forEach(block => {
-            this._ctx.strokeRect(block.x, block.y, block.width, block.height);
-        });
-    }
 }
 
 export default MarioEducational;
\ No newline at end of file