:root {
  /* Brand colors */
  --color-primary: #0d6efd;
  --color-primary-dark: #0056b3;
  --color-secondary: #0056b3;
  --color-accent: #198754;

  /* Neutral colors */
  --color-text: #1a1a1a;
  --color-text-muted: #6c757d;
  --color-background: #ffffff;
  --color-background-alt: #f8f9fa;
  --color-border: #dee2e6;

  /* Status colors */
  --color-success: #198754;
  --color-info: #0dcaf0;
  --color-warning: #ffc107;
  --color-danger: #dc3545;

  /* Typography */
  --font-family-base: 'Segoe UI', system-ui, -apple-system, BlinkMacSystemFont, 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  --font-size-base: 1rem;
  --font-size-sm: 0.875rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --line-height-base: 1.65;
  --line-height-heading: 1.2;

  /* Spacing scale */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 32px;
  --space-6: 48px;
  --space-7: 64px;
  --space-8: 96px;

  /* Layout */
  --max-content-width: 1000px;
  --border-radius-card: 12px;
  --border-radius-button: 8px;
  --header-height: 72px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 40px rgba(13, 110, 253, 0.15);

  /* Transitions */
  --transition-base: 200ms ease-in-out;
  --transition-smooth: 300ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Gradients */
  --gradient-hero: radial-gradient(ellipse at top left, rgba(13, 110, 253, 0.12) 0%, transparent 50%),
                    radial-gradient(ellipse at bottom right, rgba(25, 135, 84, 0.08) 0%, transparent 50%),
                    linear-gradient(180deg, var(--color-background-alt) 0%, var(--color-background) 100%);
  --gradient-text: linear-gradient(135deg, var(--color-primary) 0%, #6610f2 50%, var(--color-primary-dark) 100%);
}

html.dark {
  --color-text: #f1f3f5;
  --color-text-muted: #adb5bd;
  --color-background: #0f172a;
  --color-background-alt: #1e293b;
  --color-border: #334155;
  --color-success: #20c997;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px rgba(13, 110, 253, 0.25);

  --gradient-hero: radial-gradient(ellipse at top left, rgba(13, 110, 253, 0.2) 0%, transparent 50%),
                    radial-gradient(ellipse at bottom right, rgba(25, 135, 84, 0.12) 0%, transparent 50%),
                    linear-gradient(180deg, #0f172a 0%, #1e293b 100%);
}