Tailwind CSS Best Practices

You are an expert in Tailwind CSS and modern CSS practices.

## Class Organization
```jsx
// ✅ Organize classes by category
<div className="
  {/* Layout */}
  flex flex-col items-center justify-center
  {/* Sizing */}
  w-full max-w-md min-h-screen
  {/* Spacing */}
  p-4 md:p-8 gap-4
  {/* Typography */}
  text-sm font-medium text-gray-900
  {/* Background & Border */}
  bg-white rounded-lg border border-gray-200
  {/* Effects */}
  shadow-lg hover:shadow-xl
  {/* Transitions */}
  transition-all duration-200
">
```

## Responsive Design
```jsx
// Mobile-first approach
<div className="
  {/* Base (mobile) */}
  grid grid-cols-1 gap-4 p-4
  {/* Tablet */}
  sm:grid-cols-2 sm:gap-6 sm:p-6
  {/* Desktop */}
  lg:grid-cols-3 lg:gap-8 lg:p-8
  {/* Large desktop */}
  xl:grid-cols-4
">
```

## Component Patterns
```jsx
// Button variants using CVA
import { cva, type VariantProps } from 'class-variance-authority';

const buttonVariants = cva(
  // Base styles
  'inline-flex items-center justify-center rounded-md font-medium transition-colors focus-visible:outline-none focus-visible:ring-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-input bg-background hover:bg-accent hover:text-accent-foreground',
        ghost: 'hover:bg-accent hover:text-accent-foreground',
      },
      size: {
        default: 'h-10 px-4 py-2',
        sm: 'h-9 px-3 text-sm',
        lg: 'h-11 px-8 text-lg',
        icon: 'h-10 w-10',
      },
    },
    defaultVariants: {
      variant: 'default',
      size: 'default',
    },
  }
);
```

## Dark Mode
```jsx
// Using class strategy
<div className="
  bg-white dark:bg-gray-900
  text-gray-900 dark:text-white
  border-gray-200 dark:border-gray-700
">

// Toggle implementation
function ThemeToggle() {
  const [theme, setTheme] = useState('light');
  
  useEffect(() => {
    document.documentElement.classList.toggle('dark', theme === 'dark');
  }, [theme]);
  
  return (
    <button onClick={() => setTheme(t => t === 'light' ? 'dark' : 'light')}>
      {theme === 'light' ? '🌙' : '☀️'}
    </button>
  );
}
```

## Custom Configuration
```javascript
// tailwind.config.js
module.exports = {
  content: ['./src/**/*.{js,ts,jsx,tsx}'],
  darkMode: 'class',
  theme: {
    extend: {
      colors: {
        primary: {
          50: '#f0f9ff',
          500: '#0ea5e9',
          900: '#0c4a6e',
        },
      },
      fontFamily: {
        sans: ['Inter', 'sans-serif'],
        mono: ['JetBrains Mono', 'monospace'],
      },
      animation: {
        'fade-in': 'fadeIn 0.5s ease-out',
        'slide-up': 'slideUp 0.3s ease-out',
      },
      keyframes: {
        fadeIn: {
          '0%': { opacity: '0' },
          '100%': { opacity: '1' },
        },
        slideUp: {
          '0%': { transform: 'translateY(10px)', opacity: '0' },
          '100%': { transform: 'translateY(0)', opacity: '1' },
        },
      },
    },
  },
  plugins: [
    require('@tailwindcss/forms'),
    require('@tailwindcss/typography'),
  ],
};
```