:root {
  /* Colors - Light Mode */
  --color-bg: #ffffff;
  --color-bg-secondary: #f5f5f5;
  --color-bg-tertiary: #fafafa;
  --color-text: #1a1a1a;
  --color-text-secondary: #666666;
  --color-text-tertiary: #999999;
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #dbeafe;
  --color-success: #16a34a;
  --color-success-light: #dcfce7;
  --color-warning: #ca8a04;
  --color-warning-light: #fef3c7;
  --color-error: #dc2626;
  --color-error-light: #fee2e2;
  --color-border: #e5e5e5;
  --color-border-light: #f0f0f0;

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

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', Consolas, 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;

  /* Line heights */
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.75;

  /* Borders */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 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);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Z-index */
  --z-dropdown: 1000;
  --z-modal: 2000;
  --z-toast: 3000;
}

/* Dark Mode - System Preference */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg: #1a1a1a;
    --color-bg-secondary: #2a2a2a;
    --color-bg-tertiary: #333333;
    --color-text: #f5f5f5;
    --color-text-secondary: #a0a0a0;
    --color-text-tertiary: #707070;
    --color-border: #404040;
    --color-border-light: #353535;
    --color-primary-light: #1e3a8a;
    --color-success-light: #14532d;
    --color-warning-light: #713f12;
    --color-error-light: #7f1d1d;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
  }
}

/* Manual Dark Mode Toggle */
[data-theme="dark"] {
  --color-bg: #1a1a1a;
  --color-bg-secondary: #2a2a2a;
  --color-bg-tertiary: #333333;
  --color-text: #f5f5f5;
  --color-text-secondary: #a0a0a0;
  --color-text-tertiary: #707070;
  --color-border: #404040;
  --color-border-light: #353535;
  --color-primary-light: #1e3a8a;
  --color-success-light: #14532d;
  --color-warning-light: #713f12;
  --color-error-light: #7f1d1d;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
}