Design Tokens and Theming

Consistent design through tokens.

What Are Design Tokens?

css
/* Design tokens as CSS variables */
:root {
  /* Colors */
  --color-primary: #3b82f6;
  --color-primary-hover: #2563eb;
  --color-secondary: #6b7280;
  --color-danger: #ef4444;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  
  /* Typography */
  --font-family: 'Inter', system-ui, sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-md: 1rem;
  --font-size-lg: 1.25rem;
  
  /* Border radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 1rem;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
}

TypeScript Tokens

tsx
// tokens/index.ts
export const colors = {
  primary: 'var(--color-primary)',
  secondary: 'var(--color-secondary)',
  danger: 'var(--color-danger)',
} as const;

export const spacing = {
  xs: 'var(--spacing-xs)',
  sm: 'var(--spacing-sm)',
  md: 'var(--spacing-md)',
  lg: 'var(--spacing-lg)',
  xl: 'var(--spacing-xl)',
} as const;

export type Color = keyof typeof colors;
export type Spacing = keyof typeof spacing;

Theme Context

tsx
type Theme = 'light' | 'dark';

const ThemeContext = createContext<{
  theme: Theme;
  setTheme: (theme: Theme) => void;
} | null>(null);

export function ThemeProvider({ children }: { children: React.ReactNode }) {
  const [theme, setTheme] = useState<Theme>(() => {
    if (typeof window !== 'undefined') {
      return localStorage.getItem('theme') as Theme || 'light';
    }
    return 'light';
  });
  
  useEffect(() => {
    document.documentElement.dataset.theme = theme;
    localStorage.setItem('theme', theme);
  }, [theme]);
  
  return (
    <ThemeContext.Provider value={{ theme, setTheme }}>
      {children}
    </ThemeContext.Provider>
  );
}

export function useTheme() {
  const context = useContext(ThemeContext);
  if (!context) throw new Error('useTheme must be used within ThemeProvider');
  return context;
}

Dark Mode Tokens

css
:root {
  --color-bg: #ffffff;
  --color-text: #1f2937;
  --color-border: #e5e7eb;
}

[data-theme='dark'] {
  --color-bg: #1f2937;
  --color-text: #f9fafb;
  --color-border: #374151;
}

Tailwind Config with Tokens

js
// tailwind.config.js
module.exports = {
  theme: {
    extend: {
      colors: {
        primary: 'var(--color-primary)',
        secondary: 'var(--color-secondary)',
      },
      spacing: {
        xs: 'var(--spacing-xs)',
        sm: 'var(--spacing-sm)',
      },
    },
  },
};