Transform Sudoku game into level-based progression system with modern UI

[Copilot]

Transforms the Sudoku game from a simple difficulty selection mode into a level-based progression system (闯关式) with a modern, beautified user interface, referencing mainstream Sudoku gameplay patterns for a more engaging experience.

Changes

Level Progression System

• 20 sequential levels across 5 difficulty tiers (4 levels per difficulty)
• Automatic level unlocking upon completion
• Progress tracking via UserDefaults (current level and max unlocked level)
• Level selection interface showing lock status and completion state

Game Logic (LTSudokuLogic)

• Added currentLevel and maxUnlockedLevel properties
• New methods: getCurrentLevel(), setCurrentLevel(), getMaxUnlockedLevel(), unlockNextLevel()
• getDifficultyForLevel(): Maps level numbers to difficulty settings
• getLevelName(): Generates display names for each level
• Modified initGameData() to generate puzzles based on current level

UI Beautification

• Modern Design Elements: Soft blue color palette with gradients throughout
• Level Label: Blue background with rounded corners, white bold text (20px), improved spacing (40px height)
• Enhanced Buttons:
  • Save button: Green background with 💾 emoji icon
  • Load button: Orange background with 📂 emoji icon
  • Rounded corners (8px), shadow effects, larger size (80x35px)
• Sudoku Grid: Subtle shadow effects (opacity 0.15, radius 8px), rounded corners for depth
• Background Gradients: Soft blue gradient creating modern, polished appearance
• Level Selection Screen:
  • Card-style cells with individual shadows and rounded corners (10px)
  • Increased row height to 60px for better touch targets
  • Rich visual indicators: ▶️ for current level (blue highlight), ✅ for completed (green), 🔒 for locked (gray)
  • Tap animation feedback for better UX
  • Clean design without separators
• Victory Alert:
  • Celebration emoji (🎉, 🏆)
  • Icon-enhanced button text (▶️ Next, 🔄 Replay, 🎊 Done)
  • Special trophy message for completing all levels

Core Files Modified

• LTGlobalState.h: Added level tracking constants (CURRENTLEVEL, MAXUNLOCKEDLEVEL, MAXLEVEL)
• LTSudokuLogic.h/.m: Level management system implementation
• LTSudukuGameView.m: Level display, progression UI, and visual enhancements
• LTSettingViewController.m: Beautified level selection interface with card design
• ViewController.m: Added gradient background
• README.md: Updated documentation to reflect level-based system

Level Design

Levels	Difficulty	Blank Cells (per 3x3)
1-4	低级 (Easy)	2
5-8	中级 (Medium)	4
9-12	高级 (Hard)	6
13-16	专家级 (Expert)	7
17-20	骨灰级 (Master)	8

Design Principles

• Consistent soft blue color palette throughout
• Professional shadow effects for visual depth
• Rounded corners for modern, friendly appearance
• Emoji icons for quick visual recognition
• Better spacing and padding for improved usability
• Touch-friendly button sizes

The progression system combined with the modern UI provides a structured, visually appealing, goal-oriented experience that encourages players to advance through increasingly challenging puzzles, similar to popular mobile Sudoku applications.

Original prompt

完善这个demo，让游戏支持更多关卡

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[lt541013990]

@copilot 参考一下市面的普通数独玩法，改造一下当前的游戏模式，变成闯关式的

[Copilot]

@copilot 参考一下市面的普通数独玩法，改造一下当前的游戏模式，变成闯关式的

已完成闯关式改造！实现了20个关卡的渐进式游戏模式：

核心功能：

• 20个关卡分5个难度梯度（每难度4关）
• 完成关卡自动解锁下一关
• 关卡选择界面显示解锁状态
• 游戏界面显示当前关卡信息
• 通关提示支持"下一关"和"重玩本关"选项

关卡设计：

• 第1-4关：低级难度
• 第5-8关：中级难度
• 第9-12关：高级难度
• 第13-16关：专家级难度
• 第17-20关：骨灰级难度

参考主流数独游戏的渐进式体验设计。commit: 35ef87e

[lt541013990]

@copilot 目前的UI比较简陋，美化一下

[Copilot]

@copilot 目前的UI比较简陋，美化一下

已完成UI美化！主要改进：

视觉增强：

• 🎨 关卡标签：蓝色背景、圆角、大号字体
• 💾 按钮升级：彩色设计（绿色存档、橙色读档）、圆角阴影、emoji图标
• 🎮 数独棋盘：添加阴影效果和圆角，视觉层次更丰富
• 🎯 渐变背景：柔和的蓝色渐变，提升整体美感

关卡选择界面：

• 📱 卡片式设计，每个关卡独立阴影
• ✨ 状态图标：▶️当前、✅已完成、🔒未解锁
• 📏 增大行高至60px，更易操作
• 🎭 点击动画反馈

通关提示：

• 🎉 庆祝emoji和更好的文案
• 🏆 通关所有关卡有特别祝贺

整体采用现代化设计语言，色彩丰富协调，视觉层次清晰。commit: 8495df7