This repository provides a CSS library that replicates GitHub's Markdown styling for web content. The main entry point is `github-markdown.css`, which uses CSS custom properties and media queries to automatically switch between light and dark themes based on user system preferences. The library is designed to be included in web projects by linking the CSS file and applying the `markdown-body` class to containers of Markdown-rendered HTML. The project includes multiple theme variants (light-only, dark-only, high contrast, colorblind) generated from a common source, demonstrating a maintainable approach to theme management. The CSS is generated by the `generate-github-markdown-css` tool, ensuring consistency and accuracy to GitHub's styling. The repository also contains a demo `index.html` showcasing the CSS in action with proper layout constraints. The codebase is actively maintained with recent updates, has no external runtime dependencies, and follows modern CSS practices. While the library itself is focused and singular in purpose, the CSS output is comprehensive and non-trivial, capturing numerous details of GitHub's Markdown rendering including syntax highlighting, tables, code blocks, and interactive elements.