:root {
  /* --- Colors --- */
  /* Primary Brand (Indigo/Blue) */
  --color-primary-50: #eef2ff;
  --color-primary-100: #e0e7ff;
  --color-primary-200: #c7d2fe;
  --color-primary-300: #a5b4fc;
  --color-primary-400: #818cf8;
  --color-primary-500: #6366f1;
  --color-primary-600: #4f46e5;
  --color-primary-700: #4338ca;
  --color-primary-800: #3730a3;
  --color-primary-900: #312e81;

  /* Neutrals (Slate) */
  --color-gray-50: #f8fafc;
  --color-gray-100: #f1f5f9;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e1;
  --color-gray-400: #94a3b8;
  --color-gray-500: #64748b;
  --color-gray-600: #475569;
  --color-gray-700: #334155;
  --color-gray-800: #1e293b;
  --color-gray-900: #0f172a;

  /* Semantic */
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --color-info: #3b82f6;

  /* Surfaces */
  --bg-body: var(--color-gray-50);
  --bg-card: #ffffff;
  --bg-input: #ffffff;
  --text-main: var(--color-gray-900);
  --text-muted: var(--color-gray-500);
  --text-inverted: #ffffff;

  /* --- Typography --- */
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  
  --text-xs: 0.75rem;   /* 12px */
  --text-sm: 0.875rem;  /* 14px */
  --text-base: 1rem;    /* 16px */
  --text-lg: 1.125rem;  /* 18px */
  --text-xl: 1.25rem;   /* 20px */
  --text-2xl: 1.5rem;   /* 24px */
  --text-3xl: 1.875rem; /* 30px */

  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-bold: 600;
  --font-weight-black: 700;

  /* --- Spacing --- */
  --space-1: 0.25rem;  /* 4px */
  --space-2: 0.5rem;   /* 8px */
  --space-3: 0.75rem;  /* 12px */
  --space-4: 1rem;     /* 16px */
  --space-6: 1.5rem;   /* 24px */
  --space-8: 2rem;     /* 32px */
  --space-12: 3rem;    /* 48px */

  /* --- Borders & Radius --- */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  --border-width: 1px;
  --border-color: var(--color-gray-200);

  /* --- Shadows --- */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);

  /* --- Transitions --- */
  --transition-base: all 0.2s ease-in-out;
}