:root {
  /* ========================================
     Colors
     ======================================== */

  /* Primary colors */
  --color-primary: #1a1a2e;
  --color-primary-dark: #0f0f1a;
  --color-accent: #4a90d9;
  --color-accent-dim: #3a7bc8;

  /* Semantic colors */
  --color-success: #4caf50;
  --color-success-dark: #45a049;
  --color-danger: #f44336;
  --color-warning: #ff9800;

  /* Neutral colors */
  --color-white: #ffffff;
  --color-black: #000000;
  --color-gray: #999999;

  /* Alpha colors (backgrounds) */
  --color-white-alpha-5: rgba(255, 255, 255, 0.05);
  --color-white-alpha-10: rgba(255, 255, 255, 0.1);
  --color-white-alpha-15: rgba(255, 255, 255, 0.15);
  --color-white-alpha-20: rgba(255, 255, 255, 0.2);
  --color-white-alpha-30: rgba(255, 255, 255, 0.3);
  --color-white-alpha-70: rgba(255, 255, 255, 0.7);
  --color-white-alpha-80: rgba(255, 255, 255, 0.8);
  --color-white-alpha-90: rgba(255, 255, 255, 0.9);

  --color-black-alpha-10: rgba(0, 0, 0, 0.1);
  --color-black-alpha-20: rgba(0, 0, 0, 0.2);
  --color-black-alpha-30: rgba(0, 0, 0, 0.3);
  --color-black-alpha-40: rgba(0, 0, 0, 0.4);

  --color-accent-alpha-20: rgba(74, 144, 217, 0.2);
  --color-accent-alpha-30: rgba(74, 144, 217, 0.3);
  --color-accent-alpha-40: rgba(74, 144, 217, 0.4);

  --color-success-alpha-20: rgba(76, 175, 80, 0.2);
  --color-success-alpha-30: rgba(76, 175, 80, 0.3);
  --color-success-alpha-40: rgba(76, 175, 80, 0.4);
  --color-success-alpha-50: rgba(76, 175, 80, 0.5);

  --color-danger-alpha-20: rgba(244, 67, 54, 0.2);
  --color-danger-alpha-40: rgba(244, 67, 54, 0.4);
  --color-danger-alpha-50: rgba(244, 67, 54, 0.5);

  /* ========================================
     Spacing Scale
     ======================================== */

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  /* Legacy px-based spacing */
  --space-2: 2px;
  --space-3: 3px;
  --space-4: 4px;
  --space-6: 6px;
  --space-8: 8px;
  --space-10: 10px;
  --space-12: 12px;
  --space-15: 15px;
  --space-16: 16px;
  --space-20: 20px;
  --space-24: 24px;
  --space-25: 25px;
  --space-30: 30px;
  --space-40: 40px;
  --space-60: 60px;

  /* ========================================
     Typography
     ======================================== */

  /* Font sizes (rem-based) */
  --font-xs: 0.75rem;
  --font-sm: 0.875rem;
  --font-base: 1rem;
  --font-lg: 1.125rem;
  --font-xl: 1.25rem;
  --font-2xl: 1.5rem;
  --font-3xl: 1.875rem;

  /* Font sizes (em-based for relative sizing) */
  --font-em-xs: 0.65em;
  --font-em-sm: 0.75em;
  --font-em-md: 0.85em;
  --font-em-base: 0.9em;
  --font-em-lg: 1.1em;
  --font-em-xl: 1.3em;
  --font-em-2xl: 1.8em;

  /* Font weights */
  --font-weight-normal: 400;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* ========================================
     Border Radius
     ======================================== */

  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 10px;
  --radius-2xl: 12px;
  --radius-3xl: 15px;
  --radius-full: 9999px;

  /* ========================================
     Effects
     ======================================== */

  /* Glass-morphism */
  --glass-bg: rgba(255, 255, 255, 0.1);
  --glass-bg-light: rgba(255, 255, 255, 0.15);
  --glass-border: rgba(255, 255, 255, 0.2);
  --glass-blur: blur(10px);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.4);

  /* Text shadows */
  --text-shadow-glow: 0 0 10px currentColor;
  --text-shadow-glow-lg: 0 0 10px currentColor, 0 0 20px currentColor;

  /* Glow effects (for active states) */
  --glow-accent: 0 0 10px var(--color-accent), 0 0 20px var(--color-accent);
  --glow-success: 0 0 10px var(--color-success-alpha-50);
  --glow-danger: 0 0 10px var(--color-danger-alpha-50);

  /* ========================================
     Transitions
     ======================================== */

  --transition-fast: 0.2s;
  --transition-base: 0.3s;
  --transition-slow: 0.5s;

  /* ========================================
     Layout Constraints
     ======================================== */

  --max-width-container: 1200px;
  --max-width-content: 800px;
  --max-width-form: 400px;

  /* ========================================
     Z-index Scale
     ======================================== */

  --z-base: 1;
  --z-dropdown: 100;
  --z-modal: 1000;
}