Master CSS is a comprehensive CSS framework and toolchain that enables writing CSS directly in class attributes using a concise utility syntax. The system supports multiple rendering modes: a runtime engine that dynamically generates and injects CSS in the browser, a static build-time compilation mode for zero-runtime production output, and progressive hybrid modes that pre-generate critical CSS and hydrate on the client. It includes a fully modular architecture with over 30 packages covering a core engine, compiler, scanner for class extraction, validator, language server, ESLint plugin, CLI, MCP server, and first-class integration plugins for Vite, Next.js, Nuxt, Astro, Svelte, Webpack, and more. The codebase is production-grade with extensive unit and e2e tests, a dedicated benchmarking suite measuring CSS output sizes, build timings, and browser lifecycle performance, and a documentation site with interactive playground. While primarily a JavaScript/TypeScript application library, it also contains benchmark infrastructure that produces analytical metrics. The architecture is strongly layered with well-defined schema contracts (manifest JSON) enabling loose coupling between packages.
React Code View is a React component library for rendering code with live preview and syntax highlighting. It provides a CodeView component that combines an editable code editor, live preview, and syntax highlighting, allowing developers to create interactive code examples. The library includes build tool plugins (unplugin) for Vite, Webpack, Rollup, esbuild, and Rspack that enable importing markdown files as React components with automatic code block processing. At its core, it uses Sucrase for JSX/TS transformation, Shiki for syntax highlighting, and CodeMirror 6 for the editing experience, with code execution happening in a sandboxed environment.