Minesweeper

# Minesweeper PRD

## Overview
Build a classic Minesweeper game with multiple difficulty levels, flagging mechanics, flood-fill auto-reveal, and a polished UI with timer and high scores.

## Requirements
- Three difficulty levels: Beginner (9x9, 10 mines), Intermediate (16x16, 40 mines), Expert (30x16, 99 mines)
- Custom grid size option with configurable mine count
- Left-click to reveal a cell
- Right-click to flag or unflag a cell
- Auto-reveal empty neighbors using flood fill algorithm
- Number display (1-8) with distinct colors per number
- First click is never a mine (regenerate board if needed)
- Mine counter showing total mines minus placed flags
- Timer starting from first click
- Win detection when all non-mine cells are revealed
- Loss detection when a mine is clicked, revealing all mines
- Flag counter display
- Smiley face button to restart the game
- High scores per difficulty level persisted to localStorage
- Keyboard-accessible cells for navigation
- Visual mine explosion animation on loss

## Tech Stack
- JavaScript or any frontend framework
- CSS for grid layout and animations
- No game libraries

## Scoring Criteria
- **Functional (40%)**: Core gameplay works, mines generate correctly, flood fill works, win/loss detection works
- **Quality (20%)**: Clean code, no bugs in edge cases, smooth cell interactions
- **Fidelity (25%)**: All features present including custom size, timer, high scores, and animations
- **Speed (15%)**: Time bonus