mdui is a comprehensive Web Component library implementing Material Design 3 (Material You). It provides over 30 reusable UI components (buttons, dialogs, navigation, forms, etc.) built with Lit, supporting dynamic color theming, dark/light modes, and localization across 60+ languages. The library is framework-agnostic and can be used directly in HTML or with any frontend framework. It includes a bundled jQuery-like utility (@mdui/jq) for DOM manipulation, a Model Context Protocol (MCP) server for AI-assisted development tooling, and IDE plugins for VS Code and JetBrains. The codebase is well-structured with a monorepo managed by pnpm, featuring shared mixins, controllers, and decorators that promote consistency across components. The project is actively maintained with recent commits, comprehensive documentation, and a large demo site.