/* Design Tokens - Single source of truth for design values */
:root {
  /* Colors - Light Theme */
  --color-bg: #ffffff;
  --color-bg-secondary: #f8f9fa;
  --color-bg-tertiary: #e9ecef;
  --color-text: #212529;
  --color-text-secondary: #495057;
  --color-text-muted: #6c757d;
  --color-border: #dee2e6;
  --color-border-light: #e9ecef;

  --color-primary: #0066cc;
  --color-primary-hover: #0052a3;
  --color-primary-light: #e6f0fa;

  --color-accent: #6366f1;
  --color-accent-hover: #4f46e5;

  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-error: #ef4444;

  --color-code-bg: #f1f3f5;
  --color-code-text: #e83e8c;

  --color-link: var(--color-primary);
  --color-link-hover: var(--color-primary-hover);
  --color-link-visited: #5a3d7a;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", Menlo, Consolas, monospace;

  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  --letter-spacing-tight: -0.025em;
  --letter-spacing-normal: 0;
  --letter-spacing-wide: 0.025em;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* Layout */
  --container-max: 1200px;
  --container-narrow: 720px;
  --header-height: 64px;

  /* Borders */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;

  /* Z-index */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-modal: 300;
  --z-tooltip: 400;
}