# Base Components

Reference implementations for core UI primitives. Each uses `cn` (see config-and-utilities.md) and consumes the design tokens.

## Button

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

const buttonVariants = cva(
  'inline-flex items-center justify-center rounded-md font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-offset-2 disabled:pointer-events-none disabled:opacity-50',
  {
    variants: {
      variant: {
        primary: 'bg-primary-500 text-white hover:bg-primary-600',
        secondary: 'bg-gray-100 text-gray-900 hover:bg-gray-200',
        outline: 'border border-gray-300 bg-transparent hover:bg-gray-50',
        ghost: 'hover:bg-gray-100',
        destructive: 'bg-red-500 text-white hover:bg-red-600',
        link: 'text-primary-500 underline-offset-4 hover:underline',
      },
      size: {
        sm: 'h-8 px-3 text-sm',
        md: 'h-10 px-4',
        lg: 'h-12 px-6 text-lg',
        icon: 'h-10 w-10',
      },
    },
    defaultVariants: {
      variant: 'primary',
      size: 'md',
    },
  }
);

interface ButtonProps
  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
    VariantProps<typeof buttonVariants> {
  isLoading?: boolean;
}

export function Button({
  className,
  variant,
  size,
  isLoading,
  children,
  disabled,
  ...props
}: ButtonProps) {
  return (
    <button
      className={cn(buttonVariants({ variant, size }), className)}
      disabled={disabled || isLoading}
      {...props}
    >
      {isLoading && <Spinner className="mr-2 h-4 w-4" />}
      {children}
    </button>
  );
}
```

## Input

```tsx
// components/ui/input.tsx
import { cn } from '@/lib/utils';
import { forwardRef } from 'react';

interface InputProps extends React.InputHTMLAttributes<HTMLInputElement> {
  error?: string;
}

export const Input = forwardRef<HTMLInputElement, InputProps>(
  ({ className, error, ...props }, ref) => {
    return (
      <div className="space-y-1">
        <input
          ref={ref}
          className={cn(
            'flex h-10 w-full rounded-md border bg-white px-3 py-2 text-sm',
            'placeholder:text-gray-400',
            'focus:outline-none focus:ring-2 focus:ring-primary-500 focus:border-transparent',
            'disabled:cursor-not-allowed disabled:opacity-50',
            error ? 'border-red-500' : 'border-gray-300',
            className
          )}
          aria-invalid={!!error}
          {...props}
        />
        {error && (
          <p className="text-sm text-red-500" role="alert">
            {error}
          </p>
        )}
      </div>
    );
  }
);

Input.displayName = 'Input';
```

## Card

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

interface CardProps extends React.HTMLAttributes<HTMLDivElement> {}

export function Card({ className, ...props }: CardProps) {
  return (
    <div
      className={cn(
        'rounded-lg border bg-white shadow-sm',
        className
      )}
      {...props}
    />
  );
}

export function CardHeader({ className, ...props }: CardProps) {
  return <div className={cn('p-6 pb-0', className)} {...props} />;
}

export function CardTitle({ className, ...props }: CardProps) {
  return <h3 className={cn('text-lg font-semibold', className)} {...props} />;
}

export function CardContent({ className, ...props }: CardProps) {
  return <div className={cn('p-6', className)} {...props} />;
}

export function CardFooter({ className, ...props }: CardProps) {
  return <div className={cn('p-6 pt-0 flex gap-2', className)} {...props} />;
}
```

## Component Index

Re-export every shipped component from a single barrel. Add exports as each component is implemented.

```typescript
// components/ui/index.ts
export { Button } from './button';
export { Input } from './input';
export { Card, CardHeader, CardTitle, CardContent, CardFooter } from './card';
export { Badge } from './badge';
export { Avatar } from './avatar';
export { Select } from './select';
export { Checkbox } from './checkbox';
export { Radio } from './radio';
export { Switch } from './switch';
export { Modal } from './modal';
export { Toast } from './toast';
export { Tabs } from './tabs';
export { Dropdown } from './dropdown';
```

# Config and Utilities

Wiring that binds tokens and components into the build: the Tailwind config and the `cn` class-merge helper.

## Tailwind Config

```javascript
// tailwind.config.js
const { colors, typography, spacing, shadows, radii } = require('./tokens');

module.exports = {
  content: ['./src/**/*.{js,ts,jsx,tsx}'],
  darkMode: 'class',
  theme: {
    extend: {
      colors: {
        primary: colors.primary,
        gray: colors.gray,
        success: colors.success,
        warning: colors.warning,
        error: colors.error,
      },
      fontFamily: typography.fontFamily,
      fontSize: typography.fontSize,
      spacing: spacing,
      boxShadow: shadows,
      borderRadius: radii,
    },
  },
  plugins: [],
};
```

## Utility Function

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

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

# Design Tokens

Reference token definitions for colors, typography, spacing, shadows, and radii. Adapt values to the project brand before shipping.

## Colors

```typescript
// tokens/colors.ts
export const colors = {
  // Brand
  primary: {
    50: '#eff6ff',
    100: '#dbeafe',
    200: '#bfdbfe',
    300: '#93c5fd',
    400: '#60a5fa',
    500: '#3b82f6', // Main
    600: '#2563eb',
    700: '#1d4ed8',
    800: '#1e40af',
    900: '#1e3a8a',
  },

  // Semantic
  success: {
    light: '#dcfce7',
    main: '#22c55e',
    dark: '#15803d',
  },
  warning: {
    light: '#fef3c7',
    main: '#f59e0b',
    dark: '#b45309',
  },
  error: {
    light: '#fee2e2',
    main: '#ef4444',
    dark: '#b91c1c',
  },

  // Neutral
  gray: {
    50: '#f9fafb',
    100: '#f3f4f6',
    200: '#e5e7eb',
    300: '#d1d5db',
    400: '#9ca3af',
    500: '#6b7280',
    600: '#4b5563',
    700: '#374151',
    800: '#1f2937',
    900: '#111827',
  },
} as const;
```

## Typography

```typescript
// tokens/typography.ts
export const typography = {
  fontFamily: {
    sans: ['Inter', 'system-ui', 'sans-serif'],
    mono: ['JetBrains Mono', 'monospace'],
  },

  fontSize: {
    xs: ['0.75rem', { lineHeight: '1rem' }],
    sm: ['0.875rem', { lineHeight: '1.25rem' }],
    base: ['1rem', { lineHeight: '1.5rem' }],
    lg: ['1.125rem', { lineHeight: '1.75rem' }],
    xl: ['1.25rem', { lineHeight: '1.75rem' }],
    '2xl': ['1.5rem', { lineHeight: '2rem' }],
    '3xl': ['1.875rem', { lineHeight: '2.25rem' }],
    '4xl': ['2.25rem', { lineHeight: '2.5rem' }],
    '5xl': ['3rem', { lineHeight: '1.15' }],
  },

  fontWeight: {
    normal: '400',
    medium: '500',
    semibold: '600',
    bold: '700',
  },
} as const;
```

## Spacing

```typescript
// tokens/spacing.ts
export const spacing = {
  px: '1px',
  0: '0',
  0.5: '0.125rem',  // 2px
  1: '0.25rem',     // 4px
  1.5: '0.375rem',  // 6px
  2: '0.5rem',      // 8px
  2.5: '0.625rem',  // 10px
  3: '0.75rem',     // 12px
  4: '1rem',        // 16px
  5: '1.25rem',     // 20px
  6: '1.5rem',      // 24px
  8: '2rem',        // 32px
  10: '2.5rem',     // 40px
  12: '3rem',       // 48px
  16: '4rem',       // 64px
  20: '5rem',       // 80px
  24: '6rem',       // 96px
} as const;
```

## Shadows and Radii

```typescript
// tokens/effects.ts
export const shadows = {
  sm: '0 1px 2px 0 rgb(0 0 0 / 0.05)',
  DEFAULT: '0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1)',
  md: '0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1)',
  lg: '0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1)',
  xl: '0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1)',
};

export const radii = {
  none: '0',
  sm: '0.125rem',
  DEFAULT: '0.25rem',
  md: '0.375rem',
  lg: '0.5rem',
  xl: '0.75rem',
  '2xl': '1rem',
  full: '9999px',
};
```

## CSS Variables Setup

```css
/* globals.css */
:root {
  /* Colors */
  --color-primary: 59 130 246;
  --color-primary-foreground: 255 255 255;

  --color-background: 255 255 255;
  --color-foreground: 17 24 39;

  --color-muted: 243 244 246;
  --color-muted-foreground: 107 114 128;

  --color-border: 229 231 235;
  --color-ring: 59 130 246;

  /* Spacing */
  --spacing-unit: 0.25rem;

  /* Typography */
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Radii */
  --radius: 0.5rem;
}

.dark {
  --color-background: 17 24 39;
  --color-foreground: 243 244 246;
  --color-muted: 31 41 55;
  --color-muted-foreground: 156 163 175;
  --color-border: 55 65 81;
}
```