A blazingly fast, on-demand utility-first CSS framework built with Bun that generates only the CSS classes actually used in your files. It provides Tailwind CSS-compatible utility classes with full variant support (responsive, state, dark mode, pseudo-elements), arbitrary values, shortcut aliases, compile-class HTML optimization, and both CLI and programmatic APIs. Zero runtime dependencies, with 1700+ tests and benchmarks showing it outperforms UnoCSS and Tailwind in all 20 benchmark scenarios.
Crosswind targets Tailwind v4 semantics. When a utility's behavior, value scale, or validity is in question, Tailwind v4 is the reference: a class Tailwind rejects should generate nothing (never pass raw words through to CSS), and a class Tailwind accepts should produce the same declarations. Bracket syntax (flex[col jc-center]), colon syntax (bg:black), attributify mode, the compile-class transformer, and the text-shadow-* / word-spacing-* utilities are deliberate extensions beyond Tailwind — keep them working, but design them to be consistent with the same validation rules (numbers/keywords/theme values/arbitrary [...] only).
- Use pickier for linting — never use eslint directly
- Run
bunx --bun pickier .to lint,bunx --bun pickier . --fixto auto-fix - When fixing unused variable warnings, prefer
// eslint-disable-next-linecomments over prefixing with_
- Use stx for templating — never write vanilla JS (
var,document.*,window.*) in stx templates - Use crosswind as the default CSS framework which enables standard Tailwind-like utility classes
- stx
<script>tags should only contain stx-compatible code (signals, composables, directives)
- buddy-bot handles dependency updates — not renovatebot
- better-dx provides shared dev tooling as peer dependencies — do not install its peers (e.g.,
typescript,pickier,bun-plugin-dtsx) separately ifbetter-dxis already inpackage.json - If
better-dxis inpackage.json, ensurebunfig.tomlincludeslinker = "hoisted"
- Use conventional commit messages (e.g.,
fix:,feat:,chore:)