| name | tailwind |
| description | "Tailwind CSS 4.3 — CSS-first config via @theme, oklch colors, container queries, @utility/@variant, has-*/not-*/starting: variants, 3D transforms, dark mode. Use when: tailwind, tailwindcss, tailwind 4, @theme, @utility, @variant, oklch, container queries, dark mode, prose, tailwind-merge, cn() helper, postcss config. SKIP: Tailwind 3 config.js (→@theme in CSS), CSS-in-JS (styled-components)." |
🎯 Version Requirements (May 2026)
Primary pins:
Source of truth: STACK_VERSIONS.md — verified 2026-05-16
Usage
Loaded automatically when its description matches the active task. Read only the section you need, then follow the link to the relevant reference file for full detail.
Use this skill when
- Configuring Tailwind CSS 4 via the CSS-first
@theme directive (no more tailwind.config.js)
- Setting up the Vite plugin (
@tailwindcss/vite) or PostCSS plugin (@tailwindcss/postcss)
- Defining custom design tokens: colors, fonts, spacing, radius, shadows with
@theme
- Working with oklch color space for brand palettes (brand-50 through brand-900)
- Building container-query layouts with
@container and @container/{name}
- Writing custom utilities with
@utility or custom variants with @variant
- Using modern pseudo-class variants:
has-*, not-*, group-has-*, starting:
- Implementing CSS-driven dark mode (
:root / .dark class / @media prefers-color-scheme)
- Using 3D transform utilities (
rotate-x-*, rotate-y-*, perspective-*, transform-style-3d)
- Setting up
tailwind-merge + clsx as the cn() helper pattern
- Integrating with shadcn/ui component library (uses Tailwind 4 as base)
- Migrating from Tailwind 3 to Tailwind 4 (config.js → CSS-first)
- Adding
@tailwindcss/typography prose plugin for rich text rendering
Do not use this skill when
- Task is Tailwind v3 config.js migration questions only — answer inline, but remind user v4 is CSS-first
- Task is CSS-in-JS (styled-components, Emotion, vanilla-extract) — different paradigm entirely
- Task is writing component logic in React/Vue (style props only, use the appropriate framework skill)
- Task is UnoCSS, Panda CSS, or Windi CSS — different engines, different trade-offs
- Task is pure CSS Grid/Flexbox theory without Tailwind usage — use general CSS reference instead
Purpose
Tailwind CSS 4 is a full rewrite of the framework. The most important change: there is no tailwind.config.js anymore. Everything — custom tokens, plugins, variants — lives in a single CSS file via @theme, @utility, and @variant directives. The Vite plugin replaces the PostCSS pipeline for most projects. JIT is the only mode (no more AOT/PurgeCSS distinction).
Tailwind 4 also ships first-class support for container queries (no plugin required), oklch color space for perceptually uniform palettes, 3D transform utilities, has-*/not-*/starting: variants from the CSS working draft, and a dramatically improved dark mode story driven entirely by CSS cascade rather than config.
This skill covers the full Tailwind 4 workflow: initial setup, CSS-first design token authoring, modern variant patterns, migration from v3, and integration with the React + shadcn/ui ecosystem.
Capabilities
Each line below points to the canonical reference. The reference owns code, edge cases, and gotchas.
- CSS-first config —
@import "tailwindcss"; + @theme { --color-*, --font-*, --spacing-* }. NO tailwind.config.js in v4. Override defaults via @theme default {}. → references/config-css-first.md
- Design tokens — oklch lightness/chroma/hue scale (50–950); custom brand palettes in oklch for perceptual uniformity; semantic aliases (
--color-background, --color-foreground) for dark mode. → references/theme-and-tokens.md
- Modern variants —
has-[]:, not-[]:, starting: (@starting-style), group-has-[]:, peer-has-[]:, in-[]:. Stacking reads right-to-left. → references/variants.md
- Container queries — native in v4 (no plugin).
@container parent + @sm:/@lg: children; named via @container/name; units @cqw/@cqh; size @[200px]:. → references/container-queries.md
- React + shadcn integration —
@tailwindcss/vite plugin (no PostCSS); cn() = twMerge(clsx(inputs)); shadcn reads @theme vars from globals.css. → references/integration-with-react.md
- Migration v3 → v4 —
config.js → @theme; content: [] → auto-detect; darkMode: 'class' → @custom-variant dark (&:where(.dark, .dark *)); theme.extend → just declare tokens; plugins → @utility + @custom-variant. → references/migration-3-to-4.md
- @utility / @custom-variant — replace
plugin() API. @utility scrollbar-hide { ... } for custom utilities; @custom-variant dark (&:where(.dark, .dark *)); to register a prefix. →
Behavioral Traits
- Writes
@theme in the root CSS file — never reaches for tailwind.config.js in Tailwind 4 projects
- Uses oklch for all custom color tokens — never hex/rgb in
@theme (perceptual uniformity)
- Applies the
cn() helper for any conditional class logic — never string interpolation
- Chooses the Vite plugin for Vite/Next/Nuxt projects, PostCSS plugin only for legacy pipelines
- Uses semantic token names (
--color-background, --color-muted) not raw scale values in components
- Reaches for container queries (
@container) before viewport queries for component-level responsiveness
- Validates dark mode via CSS only — no JS class toggling unless the user explicitly wants manual control
- Trims
tailwind-merge to project-specific classGroups when bundle size matters
- Always reads existing
globals.css / app.css before adding tokens to avoid duplicating or overriding
Important Constraints
- NEVER create
tailwind.config.js for a Tailwind 4 project — it is not read by the v4 engine
- NEVER use hex or rgb inside
@theme color tokens — use oklch for perceptual consistency
- NEVER add
@tailwindcss/container-queries plugin — container queries are native in v4
- NEVER use
purge: config option — v4 JIT handles tree-shaking automatically
- ALWAYS set
@import "tailwindcss" as the first line of the entry CSS — not @tailwind base/components/utilities
- ALWAYS use
tailwind-merge when composing classes conditionally — naive string concat creates conflicts
- ALWAYS check if shadcn/ui
globals.css is already present before generating a new one — never overwrite it
- ALWAYS use the
@container parent marker before using container query responsive prefixes on children
Related Skills
90%-filter applied — only mainstream 2026 choices listed.
✓ marks active skills; the rest are cascade markers.
Build tooling
- ✓
vite — Vite 6 (primary Tailwind 4 integration target; @tailwindcss/vite)
Component libraries
- ✓
shadcn — shadcn/ui (most common Tailwind 4 component system for React)
Frameworks (use Tailwind as styling layer)
- ✓
react — React 19 (primary consumer of Tailwind utility classes)
- ✓
nextjs — Next.js 16 (App Router + Tailwind 4 standard pairing)
- ✓
vue — Vue 3.5
- ✓
nuxt — Nuxt 4
- ✓
astro — Astro 6 (Tailwind 4 plugin officially supported)
Validation (form + token validation)
- ✓
zod — Zod 4 (form + env validation in projects that use Tailwind for forms)
API Reference
Domain-specific references (Pattern 2) — load only what's relevant:
| Topic | File |
|---|
| Index + decision map for all reference files | references/REFERENCE.md |
| CSS-first config: @import, @theme, Vite plugin, PostCSS, prefixes | references/config-css-first.md |
| Design tokens: oklch color scale, typography, spacing, dark mode aliases | references/theme-and-tokens.md |
| Variants: has-, not-, starting:, @utility, @variant, stacking | references/variants.md |
| Container queries: @container, named containers, style queries, units | references/container-queries.md |
| React integration: cn() helper, clsx+tailwind-merge, shadcn/ui setup | references/integration-with-react.md |
| Migration from Tailwind 3 to 4: breaking changes, upgrade path | references/migration-3-to-4.md |
| Routing tests (positive/negative eval cases) | references/eval-cases.md |
Templates
Examples
How to use: navigate to the specific file for the topic you need. Don't read all files — look up only what's relevant to the current task.
