:root {
  /* Brand Colors */
  --color-primary: #3b82f6;
  --color-primary-dark: #2563eb;
  --color-primary-light: rgba(59, 130, 246, 0.15);
  --color-primary-50: rgba(59, 130, 246, 0.08);

  /* Accent */
  --color-indigo: #6366f1;
  --color-green: #10b981;
  --color-amber: #f59e0b;

  /* Dark mode surfaces */
  --color-bg: #0b1120;
  --color-surface: #131c2e;
  --color-surface-raised: #192338;

  /* Neutrals — inverted for dark mode (light text on dark bg) */
  --color-gray-900: #f1f5f9;
  --color-gray-800: #e2e8f0;
  --color-gray-700: #cbd5e1;
  --color-gray-600: #94a3b8;
  --color-gray-500: #64748b;
  --color-gray-400: #475569;
  --color-gray-300: #334155;
  --color-gray-200: #1e293b;
  --color-gray-100: #172032;
  --color-gray-50: #111827;
  --color-white: #ffffff;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Courier New', monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  --leading-tight: 1.25;
  --leading-normal: 1.6;
  --leading-relaxed: 1.75;

  /* 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: 1400px;
  --container-narrow: 800px;

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

  /* Shadows — stronger for dark mode */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.3);

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