10x faster builds
Tailwind CSS v4 is here and it's fast. The new Lightning CSS engine replaces PostCSS for the core transformation pipeline, resulting in build times that are 10x faster on large projects.
The new CSS-first configuration means you define your design tokens directly in CSS with @theme blocks. No more tailwind.config.js for most projects.
Breaking changes worth knowing
The biggest change: utilities are now auto-detected from your source files without needing a content configuration. It just works. Dark mode is also simplified with the new @variant syntax.