feat: update documentation structure and add configuration guide for better user onboarding

CONFIGURATION.md docs/configuration.md

···
 If you encounter issues not covered here:
 
 1. **Check Browser Console**: Press F12 and look for error messages
-2. **Review README**: See [README.md](./README.md) for detailed feature documentation
+2. **Review README**: See [README.md](../README.md) for detailed feature documentation
 3. **GitHub Issues**: Search existing issues or create a new one
 4. **AT Protocol Docs**: Visit [atproto.com](https://atproto.com/) for protocol details
 5. **SvelteKit Docs**: Check [kit.svelte.dev](https://kit.svelte.dev/) for framework help
···
    - Add site information via AT Protocol records
 
 2. **Deploy Your Site**:
-   - See [README.md](./README.md#-deployment) for deployment options
+   - See [README.md](../README.md#-deployment) for deployment options
    - Choose a platform (Vercel, Netlify, Cloudflare Pages, etc.)
    - Configure production environment variables
    - Set up custom domain
···
 
 ---
 
-**Configuration complete!** Your AT Protocol-powered personal website is ready to use. For detailed feature documentation, see [README.md](./README.md).
+**Configuration complete!** Your AT Protocol-powered personal website is ready to use. For detailed feature documentation, see [README.md](../README.md).

README.md

···
 
 A modern, feature-rich personal website powered by AT Protocol, built with SvelteKit 2 and Tailwind CSS 4.
 
-> **Note**: This repository contains the source code for [Ewan's Corner](https://ewancroft.uk). The current configuration (environment variables, slug mappings, static files) is specific to that website, but the codebase is designed to be easily adapted for your own AT Protocol-powered site. See [CONFIGURATION.md](./CONFIGURATION.md) for detailed setup instructions.
+> **Note**: This repository contains the source code for [Ewan's Corner](https://ewancroft.uk). The current configuration (environment variables, slug mappings, static files) is specific to that website, but the codebase is designed to be easily adapted for your own AT Protocol-powered site. See [Configuration Guide](./docs/configuration.md) for detailed setup instructions.
 
 ## 🌟 Features
 
···
 
 ## 📋 Configuration
 
-For detailed configuration instructions, see [CONFIGURATION.md](./CONFIGURATION.md).
+For detailed configuration instructions, see the [Configuration Guide](./docs/configuration.md).
 
 Quick start:
 
···
    cp .env .env.local
    ```
 
-   Edit `.env.local` with your settings (see [CONFIGURATION.md](./CONFIGURATION.md) for details)
+   Edit `.env.local` with your settings (see [Configuration Guide](./docs/configuration.md) for details)
 
 4. **Configure publication slugs** in `src/lib/config/slugs.ts`
 

docs/README.md

···
+# Documentation
+
+Welcome to the project documentation! This directory contains all technical documentation for the AT Protocol-powered personal website.
+
+## 📚 Available Documentation
+
+### [Configuration Guide](./configuration.md)
+Complete setup and configuration guide for your personal website. Covers:
+- Environment variables setup
+- Publication slug mapping
+- Static file customization
+- Optional features (WhiteWind, CORS, etc.)
+- Troubleshooting common issues
+
+**Start here if you're setting up the site for the first time.**
+
+### [Theme System](./theme-system.md)
+Documentation for the centralized color theme system. Learn how to:
+- Add new color themes
+- Customize existing themes
+- Understand the theme architecture
+- Use the theme configuration API
+
+**Read this if you want to customize or add color themes.**
+
+## 🚀 Quick Links
+
+- [Main README](../README.md) - Project overview and features
+- [Environment Example](../.env.example) - Environment variable template
+- [Theme Config](../src/lib/config/themes.config.ts) - Central theme configuration
+
+## 📖 Documentation Structure
+
+```
+docs/
+├── README.md           # This file - documentation index
+├── configuration.md    # Setup and configuration guide
+└── theme-system.md     # Theme system documentation
+```
+
+## 💡 Contributing to Documentation
+
+When adding new documentation:
+
+1. Create a new `.md` file in this directory
+2. Add it to the "Available Documentation" section above
+3. Use clear headings and examples
+4. Include a table of contents for longer documents
+5. Link to related documentation where relevant
+
+## 🔗 External Resources
+
+- [AT Protocol Documentation](https://atproto.com/)
+- [SvelteKit Documentation](https://kit.svelte.dev/)
+- [Tailwind CSS Documentation](https://tailwindcss.com/)
+- [Bluesky](https://bsky.app/)