tailwind-design-system

SKILL.md

Tailwind Design System (v4)

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

Note: This skill targets Tailwind CSS v4 (2024+). For v3 projects, refer to the upgrade guide.

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 for entry animations

Quick Start

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

/* Define your theme with @theme */
@theme {
  /* Semantic color tokens using OKLCH for better color perception */
  --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);

  /* Ring offset for focus states */
  --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 - keyframes inside @theme are output when referenced by --animate-* variables */
  --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;
  --animate-slide-out: slide-out 0.3s ease-in;

  @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;
    }
  }

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

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

/* Dark mode theme overrides */
.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-accent: oklch(22% 0.02 264);
  --color-accent-foreground: oklch(98% 0.01 264);

  --color-destructive: oklch(42% 0.15 27);
  --color-destructive-foreground: oklch(98% 0.01 264);

  --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);
}

/* Base styles */
@layer base {
  * {
    @apply border-border;
  }

  body {
    @apply bg-background text-foreground antialiased;
  }
}

Core Concepts

1. Design Token Hierarchy

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

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

2. Component Architecture

Base styles → Variants → Sizes → States → Overrides

Patterns

Pattern 1: CVA (Class Variance Authority) Components

// components/ui/button.tsx
import { Slot } from '@radix-ui/react-slot'
import { cva, type VariantProps } from 'class-variance-authority'
import { cn } from '@/lib/utils'

const buttonVariants = cva(
  // Base styles - v4 uses native CSS variables
  '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 interface ButtonProps
  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
    VariantProps<typeof buttonVariants> {
  asChild?: boolean
}

// React 19: No forwardRef needed
export function Button({
  className,
  variant,
  size,
  asChild = false,
  ref,
  ...props
}: ButtonProps & { ref?: React.Ref<HTMLButtonElement> }) {
  const Comp = asChild ? Slot : 'button'
  return (
    <Comp
      className={cn(buttonVariants({ variant, size, className }))}
      ref={ref}
      {...props}
    />
  )
}

// Usage
<Button variant="destructive" size="lg">Delete</Button>
<Button variant="outline">Cancel</Button>
<Button asChild><Link href="/home">Home</Link></Button>

Pattern 2: Compound Components (React 19)

// components/ui/card.tsx
import { cn } from '@/lib/utils'

// React 19: ref is a regular prop, no forwardRef
export function Card({
  className,
  ref,
  ...props
}: React.HTMLAttributes<HTMLDivElement> & { ref?: React.Ref<HTMLDivElement> }) {
  return (
    <div
      ref={ref}
      className={cn(
        'rounded-lg border border-border bg-card text-card-foreground shadow-sm',
        className
      )}
      {...props}
    />
  )
}

export function CardHeader({
  className,
  ref,
  ...props
}: React.HTMLAttributes<HTMLDivElement> & { ref?: React.Ref<HTMLDivElement> }) {
  return (
    <div
      ref={ref}
      className={cn('flex flex-col space-y-1.5 p-6', className)}
      {...props}
    />
  )
}

export function CardTitle({
  className,
  ref,
  ...props
}: React.HTMLAttributes<HTMLHeadingElement> & { ref?: React.Ref<HTMLHeadingElement> }) {
  return (
    <h3
      ref={ref}
      className={cn('text-2xl font-semibold leading-none tracking-tight', className)}
      {...props}
    />
  )
}

export function CardDescription({
  className,
  ref,
  ...props
}: React.HTMLAttributes<HTMLParagraphElement> & { ref?: React.Ref<HTMLParagraphElement> }) {
  return (
    <p
      ref={ref}
      className={cn('text-sm text-muted-foreground', className)}
      {...props}
    />
  )
}

export function CardContent({
  className,
  ref,
  ...props
}: React.HTMLAttributes<HTMLDivElement> & { ref?: React.Ref<HTMLDivElement> }) {
  return (
    <div ref={ref} className={cn('p-6 pt-0', className)} {...props} />
  )
}

export function CardFooter({
  className,
  ref,
  ...props
}: React.HTMLAttributes<HTMLDivElement> & { ref?: React.Ref<HTMLDivElement> }) {
  return (
    <div
      ref={ref}
      className={cn('flex items-center p-6 pt-0', className)}
      {...props}
    />
  )
}

// Usage
<Card>
  <CardHeader>
    <CardTitle>Account</CardTitle>
    <CardDescription>Manage your account settings</CardDescription>
  </CardHeader>
  <CardContent>
    <form>...</form>
  </CardContent>
  <CardFooter>
    <Button>Save</Button>
  </CardFooter>
</Card>

Pattern 3: Form Components

// components/ui/input.tsx
import { cn } from '@/lib/utils'

export interface InputProps extends React.InputHTMLAttributes<HTMLInputElement> {
  error?: string
  ref?: React.Ref<HTMLInputElement>
}

export function Input({ className, type, error, ref, ...props }: InputProps) {
  return (
    <div className="relative">
      <input
        type={type}
        className={cn(
          'flex h-10 w-full rounded-md border border-border bg-background px-3 py-2 text-sm ring-offset-background file:border-0 file:bg-transparent file:text-sm file:font-medium placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 disabled:cursor-not-allowed disabled:opacity-50',
          error && 'border-destructive focus-visible:ring-destructive',
          className
        )}
        ref={ref}
        aria-invalid={!!error}
        aria-describedby={error ? `${props.id}-error` : undefined}
        {...props}
      />
      {error && (
        <p
          id={`${props.id}-error`}
          className="mt-1 text-sm text-destructive"
          role="alert"
        >
          {error}
        </p>
      )}
    </div>
  )
}

// components/ui/label.tsx
import { cva, type VariantProps } from 'class-variance-authority'

const labelVariants = cva(
  'text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70'
)

export function Label({
  className,
  ref,
  ...props
}: React.LabelHTMLAttributes<HTMLLabelElement> & { ref?: React.Ref<HTMLLabelElement> }) {
  return (
    <label ref={ref} className={cn(labelVariants(), className)} {...props} />
  )
}

// Usage with React Hook Form + Zod
import { useForm } from 'react-hook-form'
import { zodResolver } from '@hookform/resolvers/zod'
import { z } from 'zod'

const schema = z.object({
  email: z.string().email('Invalid email address'),
  password: z.string().min(8, 'Password must be at least 8 characters'),
})

function LoginForm() {
  const { register, handleSubmit, formState: { errors } } = useForm({
    resolver: zodResolver(schema),
  })

  return (
    <form onSubmit={handleSubmit(onSubmit)} className="space-y-4">
      <div className="space-y-2">
        <Label htmlFor="email">Email</Label>
        <Input
          id="email"
          type="email"
          {...register('email')}
          error={errors.email?.message}
        />
      </div>
      <div className="space-y-2">
        <Label htmlFor="password">Password</Label>
        <Input
          id="password"
          type="password"
          {...register('password')}
          error={errors.password?.message}
        />
      </div>
      <Button type="submit" className="w-full">Sign In</Button>
    </form>
  )
}

Pattern 4: Responsive Grid System

// components/ui/grid.tsx
import { cn } from '@/lib/utils'
import { cva, type VariantProps } from 'class-variance-authority'

const gridVariants = cva('grid', {
  variants: {
    cols: {
      1: 'grid-cols-1',
      2: 'grid-cols-1 sm:grid-cols-2',
      3: 'grid-cols-1 sm:grid-cols-2 lg:grid-cols-3',
      4: 'grid-cols-1 sm:grid-cols-2 lg:grid-cols-4',
      5: 'grid-cols-2 sm:grid-cols-3 lg:grid-cols-5',
      6: 'grid-cols-2 sm:grid-cols-3 lg:grid-cols-6',
    },
    gap: {
      none: 'gap-0',
      sm: 'gap-2',
      md: 'gap-4',
      lg: 'gap-6',
      xl: 'gap-8',
    },
  },
  defaultVariants: {
    cols: 3,
    gap: 'md',
  },
})

interface GridProps
  extends React.HTMLAttributes<HTMLDivElement>,
    VariantProps<typeof gridVariants> {}

export function Grid({ className, cols, gap, ...props }: GridProps) {
  return (
    <div className={cn(gridVariants({ cols, gap, className }))} {...props} />
  )
}

// Container component
const containerVariants = cva('mx-auto w-full px-4 sm:px-6 lg:px-8', {
  variants: {
    size: {
      sm: 'max-w-screen-sm',
      md: 'max-w-screen-md',
      lg: 'max-w-screen-lg',
      xl: 'max-w-screen-xl',
      '2xl': 'max-w-screen-2xl',
      full: 'max-w-full',
    },
  },
  defaultVariants: {
    size: 'xl',
  },
})

interface ContainerProps
  extends React.HTMLAttributes<HTMLDivElement>,
    VariantProps<typeof containerVariants> {}

export function Container({ className, size, ...props }: ContainerProps) {
  return (
    <div className={cn(containerVariants({ size, className }))} {...props} />
  )
}

// Usage
<Container>
  <Grid cols={4} gap="lg">
    {products.map((product) => (
      <ProductCard key={product.id} product={product} />
    ))}
  </Grid>
</Container>

For advanced animation and dark mode patterns, see references/advanced-patterns.md:

Pattern 5: Native CSS Animations — dialog @keyframes, native popover API with @starting-style, allow-discrete transitions, and a full DialogContent/DialogOverlay implementation using Radix UI

Pattern 6: Dark Mode — ThemeProvider context with localStorage persistence, prefers-color-scheme detection, meta theme-color update, and a ThemeToggle button component

Utility Functions

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

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

// Focus ring utility
export const focusRing = cn(
  "focus-visible:outline-none focus-visible:ring-2",
  "focus-visible:ring-ring focus-visible:ring-offset-2",
);

// Disabled utility
export const disabled = "disabled:pointer-events-none disabled:opacity-50";

For advanced v4 CSS patterns, the full v3-to-v4 migration checklist, and complete best practices, see references/advanced-patterns.md:

Custom @utility — reusable CSS utilities for decorative lines and text gradients

Theme modifiers — @theme inline (reference other CSS vars), @theme static (always output), @import "tailwindcss" theme(static)

Namespace overrides — clearing default Tailwind color scales with --color-*: initial

Semi-transparent variants — color-mix() for alpha scale generation

Container queries — --container-* token definitions

v3→v4 migration checklist — 10-item checklist covering config, directives, colors, dark mode, animations, React 19 ref changes

Best practices — full Do's and Don'ts list