tailwindcss-fundamentals-v4
Installation
SKILL.md
Tailwind CSS v4 Fundamentals (2025/2026)
Overview
Tailwind CSS v4.0 was released January 22, 2025, featuring a complete rewrite with a Rust-based engine, CSS-first configuration, and significant performance improvements.
Key Changes from v3
| Feature | v3 | v4 |
|---|---|---|
| Configuration | JavaScript (tailwind.config.js) | CSS-first (@theme directive) |
| Engine | Node.js | Rust (10x faster) |
| Color format | hex/rgb | OKLCH (perceptually uniform) |
| Plugins | JS files | @plugin directive |
| Custom utilities | JS config | @utility directive |
| PostCSS imports | postcss-import | Built-in |
| Autoprefixer | Required | Built-in |
| CSS nesting | postcss-nested | Built-in |
| Content detection | Explicit config | Automatic |