Tailwind CSS
Utility-first CSS. v4 (2026) ships native `@theme` directive, OKLCH support out-of-the-box, and AI-readable CSS-first architecture. LLMs read tokens directly from CSS, no JS config to parse. Perfect for vibe coding and modern DS. On 9 September 2026, Adam Wathan announced that Tailwind Labs is joining Shopify ([official announcement](https://tailwindcss.com/blog/tailwind-is-joining-shopify)). The framework stays open source and the same team keeps maintaining it; Tailwind Plus, the paid components offer, and ui.sh are however closing new sign-ups, while existing customers keep their access.
Strengths
- v4 uses native CSS (@layer, custom properties), no complex JS config
- JIT compiler: only used classes generated, minimal bundle
- Style co-location with markup, no CSS files to juggle
- Dark mode, responsive, hover/focus/disabled states with intuitive prefixes
Limitations
- Verbose HTML classes, JSX hard to read with 20+ classes per element
- Breaking changes v3 → v4: non-trivial migration (directives, config, plugins)
- Poor abstraction for complex variants without cva or clsx
Best for
- Rapid prototyping, MVPs, solo projects or vibe coding
- Custom design systems with CSS tokens, alternative to Styled Components