# Is It Christmas?

A simple, delightful website that tells you whether today is Christmas Day (December 25th).

## Features

- **364 Days of the Year**: Shows "NO" with a sad smiley face when it's not Christmas
- **Christmas Day**: Shows "YES" with festive falling snow animation
- **Client-Side Date Checking**: Works offline using your browser's local time
- **Responsive Design**: Looks great on mobile, tablet, and desktop
- **Accessibility**: Supports `prefers-reduced-motion` for users who prefer reduced animations
- **Performance Optimized**: 60fps snow animation with particle count optimization

## Tech Stack

- **Backend**: Java 21 with standard library HttpServer (no frameworks)
- **Frontend**: Vanilla HTML, CSS, and JavaScript (no frameworks or libraries)
- **Deployment**: Docker Compose with nginx for static files
- **Zero Dependencies**: Minimal, lightweight implementation

## Quick Start

### Using Docker Compose (Recommended)

```bash
# Build and run
docker compose -f docker/docker-compose.yml up --build

# Access the application
open http://localhost
```

### Local Development

**Backend**:
```bash
cd backend
javac -d build src/main/java/christmas/*.java
java -cp build christmas.Main
```

**Frontend**:
```bash
cd frontend
python3 -m http.server 80
```

## API

### GET /api/christmas

Returns whether today is Christmas Day.

**Response**:
```json
{
  "isChristmas": false,
  "date": "2025-11-11"
}
```

## Project Structure

```
├── backend/
│   └── src/main/java/christmas/
│       ├── ChristmasChecker.java    # Date logic
│       ├── ChristmasServer.java     # HTTP server
│       └── Main.java                # Entry point
├── frontend/
│   ├── index.html                   # UI structure
│   ├── styles.css                   # Styling & animations
│   └── script.js                    # Date check & snow animation
└── docker/
    ├── Dockerfile.backend           # Java container
    ├── Dockerfile.frontend          # nginx container
    └── docker-compose.yml           # Orchestration
```

## Features Detail

### Non-Christmas Day (364 days/year)
- Large "NO" text in red
- Animated sad smiley face
- Current date display
- Responsive sizing

### Christmas Day (December 25th)
- Large "YES" text in green
- Festive "Merry Christmas" message
- Falling snow animation (Canvas API)
- 75-150 particles optimized by screen size
- Pauses when tab is hidden (Page Visibility API)
- Respects `prefers-reduced-motion`

### Midnight Transitions
- Automatically reloads at midnight to update the display
- Handles December 24→25 and December 25→26 transitions

## Development

Built following the [Specify](https://github.com/anthropics/specify) workflow:

- ✅ Spec-first planning
- ✅ User story-driven development
- ✅ Constitution-compliant (minimal dependencies, YAGNI principles)
- ✅ MVP-first implementation (P1: Non-Christmas day, P2: Christmas day)

## Performance

- Page load: < 2 seconds
- Date check: < 1 second
- Snow animation: 30-60 FPS
- Mobile optimized: 75 particles
- Desktop: 150 particles

## Browser Support

- Chrome (latest)
- Firefox (latest)
- Safari (latest)
- Edge (latest)

## License

This is a demonstration project built with Claude Code.