# Tailwind

> Tailwind v4 + DaisyUI design-system reference — CSS-first @theme config, OKLCH tokens, CVA variants, dark mode.

- Skill: `theyoungastronauts/tailwind` (Agent Skill)
- Install (CLI): `npx skillmds@latest add theyoungastronauts/tailwind`
- Raw SKILL.md: https://api.skillmd.com/api/skills/theyoungastronauts/tailwind/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: theyoungastronauts (https://skillmd.com/u/theyoungastronauts)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/theyoungastronauts/tailwind

---


# Tailwind Design System (v4)

> Adapted from [wshobson/agents](https://github.com/wshobson/agents)

Build production-ready design systems with Tailwind CSS v4, including CSS-first configuration, design tokens, component variants, responsive patterns, and accessibility.

## When to Use This Skill

- Creating a component library with Tailwind v4
- Implementing design tokens and theming with CSS-first configuration
- Building responsive and accessible components
- Standardizing UI patterns across a codebase
- Migrating from Tailwind v3 to v4
- Setting up dark mode with native CSS features

## Key v4 Changes

| v3 Pattern | v4 Pattern |
|---|---|
| `tailwind.config.ts` | `@theme` in CSS |
| `@tailwind base/components/utilities` | `@import "tailwindcss"` |
| `darkMode: "class"` | `@custom-variant dark (&:where(.dark, .dark *))` |
| `theme.extend.colors` | `@theme { --color-*: value }` |
| `require("tailwindcss-animate")` | CSS `@keyframes` in `@theme` + `@starting-style` |

## Quick Start

```css
/* app.css - Tailwind v4 CSS-first configuration */
@import "tailwindcss";

@theme {
  /* Semantic color tokens using OKLCH */
  --color-background: oklch(100% 0 0);
  --color-foreground: oklch(14.5% 0.025 264);
  --color-primary: oklch(14.5% 0.025 264);
  --color-primary-foreground: oklch(98% 0.01 264);
  --color-secondary: oklch(96% 0.01 264);
  --color-secondary-foreground: oklch(14.5% 0.025 264);
  --color-muted: oklch(96% 0.01 264);
  --color-muted-foreground: oklch(46% 0.02 264);
  --color-accent: oklch(96% 0.01 264);
  --color-accent-foreground: oklch(14.5% 0.025 264);
  --color-destructive: oklch(53% 0.22 27);
  --color-destructive-foreground: oklch(98% 0.01 264);
  --color-border: oklch(91% 0.01 264);
  --color-ring: oklch(14.5% 0.025 264);
  --color-card: oklch(100% 0 0);
  --color-card-foreground: oklch(14.5% 0.025 264);
  --color-ring-offset: oklch(100% 0 0);

  /* Radius tokens */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;

  /* Animation tokens */
  --animate-fade-in: fade-in 0.2s ease-out;
  --animate-fade-out: fade-out 0.2s ease-in;
  --animate-slide-in: slide-in 0.3s ease-out;

  @keyframes fade-in { from { opacity: 0; } to { opacity: 1; } }
  @keyframes fade-out { from { opacity: 1; } to { opacity: 0; } }
  @keyframes slide-in {
    from { transform: translateY(-0.5rem); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
  }
}

/* Dark mode */
@custom-variant dark (&:where(.dark, .dark *));

.dark {
  --color-background: oklch(14.5% 0.025 264);
  --color-foreground: oklch(98% 0.01 264);
  --color-primary: oklch(98% 0.01 264);
  --color-primary-foreground: oklch(14.5% 0.025 264);
  --color-secondary: oklch(22% 0.02 264);
  --color-secondary-foreground: oklch(98% 0.01 264);
  --color-muted: oklch(22% 0.02 264);
  --color-muted-foreground: oklch(65% 0.02 264);
  --color-border: oklch(22% 0.02 264);
  --color-ring: oklch(83% 0.02 264);
  --color-card: oklch(14.5% 0.025 264);
  --color-card-foreground: oklch(98% 0.01 264);
  --color-ring-offset: oklch(14.5% 0.025 264);
}

@layer base {
  * { @apply border-border; }
  body { @apply bg-background text-foreground antialiased; }
}
```

## Core Concepts

### Design Token Hierarchy

```
Brand Tokens (abstract)
    └── Semantic Tokens (purpose)
        └── Component Tokens (specific)

Example: oklch(45% 0.2 260) → --color-primary → bg-primary
```

### Component Architecture

```
Base styles → Variants → Sizes → States → Overrides
```

## Key Pattern: CVA Components

```tsx
import { cva, type VariantProps } from 'class-variance-authority'
import { cn } from '@/lib/utils'

const buttonVariants = cva(
  'inline-flex items-center justify-center whitespace-nowrap rounded-md text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50',
  {
    variants: {
      variant: {
        default: 'bg-primary text-primary-foreground hover:bg-primary/90',
        destructive: 'bg-destructive text-destructive-foreground hover:bg-destructive/90',
        outline: 'border border-border bg-background hover:bg-accent hover:text-accent-foreground',
        secondary: 'bg-secondary text-secondary-foreground hover:bg-secondary/80',
        ghost: 'hover:bg-accent hover:text-accent-foreground',
        link: 'text-primary underline-offset-4 hover:underline',
      },
      size: {
        default: 'h-10 px-4 py-2',
        sm: 'h-9 rounded-md px-3',
        lg: 'h-11 rounded-md px-8',
        icon: 'size-10',
      },
    },
    defaultVariants: { variant: 'default', size: 'default' },
  }
)

export function Button({ className, variant, size, asChild = false, ref, ...props }) {
  const Comp = asChild ? Slot : 'button'
  return <Comp className={cn(buttonVariants({ variant, size, className }))} ref={ref} {...props} />
}
```

## Utility Function

```ts
// lib/utils.ts
import { type ClassValue, clsx } from "clsx"
import { twMerge } from "tailwind-merge"

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs))
}
```

## Advanced v4 Patterns

### Custom Utilities

```css
@utility line-t {
  @apply relative before:absolute before:top-0 before:-left-[100vw] before:h-px before:w-[200vw] before:bg-gray-950/5 dark:before:bg-white/10;
}
```

### Namespace Overrides

```css
@theme {
  --color-*: initial; /* Clear all defaults */
  --color-white: #fff;
  --color-primary: oklch(45% 0.2 260);
}
```

### Semi-transparent Variants

```css
@theme {
  --color-primary-50: color-mix(in oklab, var(--color-primary) 5%, transparent);
  --color-primary-100: color-mix(in oklab, var(--color-primary) 10%, transparent);
}
```

## v3 to v4 Migration Checklist

- [ ] Replace `tailwind.config.ts` with CSS `@theme` block
- [ ] Change `@tailwind base/components/utilities` to `@import "tailwindcss"`
- [ ] Move color definitions to `@theme { --color-*: value }`
- [ ] Replace `darkMode: "class"` with `@custom-variant dark`
- [ ] Move `@keyframes` inside `@theme` blocks
- [ ] Replace `tailwindcss-animate` with native CSS animations
- [ ] Update `h-10 w-10` to `size-10`
- [ ] Remove `forwardRef` (React 19 passes ref as prop)
- [ ] Consider OKLCH colors for better color perception
- [ ] Replace custom plugins with `@utility` directives

## Best Practices

**Do:** Use `@theme` blocks, OKLCH colors, CVA for variants, semantic tokens (`bg-primary` not `bg-blue-500`), `size-*` shorthand, ARIA attributes + focus states

**Don't:** Use `tailwind.config.ts`, `@tailwind` directives, `forwardRef` (React 19), arbitrary values (extend `@theme` instead), hardcoded colors