The instant on-demand Atomic CSS engine.

💡 I highly recommend reading this blog post -
Reimagine Atomic CSS
for the story behind

📚 Documentation | 🧑‍💻 Interactive Docs | 🤹‍♂️ Playground | 🎓 Tutorial

Inspired by Windi CSS, Tailwind CSS, and Twind, but:

• Fully customizable - no core utilities. All functionalities are provided via presets.
• No parsing, no AST, no scanning, it's INSTANT (5x faster than Windi CSS or Tailwind JIT).
• ~6kb min+brotli - zero deps and browser friendly.
• Shortcuts - aliasing utilities, dynamically.
• Attributify mode - group utilities in attributes.
• Pure CSS Icons - use any icon as a single class.
• Variant Groups - shorthand for group utils with common prefixes.
• CSS Directives - reuse utils in CSS with @apply directive.
• Compilation mode - synthesizes multiple classes into one at build time.
• Inspector - inspect and debug interactively.
• CSS-in-JS Runtime build - use UnoCSS with one line of CDN import.
• VS Code extension
• Code-splitting for CSS - ships minimal CSS for MPA.

Read the documentation for more details.

• Vite
• Nuxt
• Astro
• Webpack
• CDN Runtime
• CLI
• VS Code extension
• ESLint Config
• PostCSS

UnoCSS is made possible thanks to the inspirations from the following projects:

in alphabetical order

• ACSS
• Bootstrap Utilities
• Chakra UI Style Props
• Semantic UI
• Tachyons
• Tailwind CSS
• Twind
• Windi CSS

MIT License © 2021-PRESENT Anthony Fu