:root {
  /* ===== Color ===== */
  --color-bg: #f4f5f7;
  --color-bg-gradient: radial-gradient(1200px 600px at 50% -10%, #eef2ff 0%, var(--color-bg) 55%);
  --color-surface: #ffffff;
  --color-surface-hover: #fafbfc;
  --color-border: #e6e8ec;
  --color-border-strong: #d4d8df;

  --color-text: #1a1d23;
  --color-text-secondary: #6b7280;
  --color-text-tertiary: #9aa1ad;

  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-soft: #eff6ff;

  --color-danger: #ef4444;
  --color-danger-hover: #dc2626;
  --color-danger-soft: #fef2f2;

  --color-success: #10b981;

  /* Structural tokens */
  --color-divider: #f3f4f6;
  --color-toast-bg: #1a1d23;
  --color-toast-fg: #ffffff;

  color-scheme: light;

  /* ===== Spacing (4px base) ===== */
  --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-16: 4rem;

  /* ===== Radius ===== */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --radius-full: 9999px;

  /* ===== Shadow ===== */
  --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.05);
  --shadow-md: 0 4px 12px rgba(16, 24, 40, 0.08);
  --shadow-lg: 0 16px 40px rgba(16, 24, 40, 0.14);

  /* ===== Typography ===== */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;

  /* ===== Motion ===== */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;

  /* ===== z-index ===== */
  --z-toast: 1000;
  --z-modal: 1100;
}

/* ===== Dark theme ===== */
[data-theme="dark"] {
  --color-bg: #0f1115;
  --color-bg-gradient: radial-gradient(1200px 600px at 50% -10%, #1a2030 0%, var(--color-bg) 55%);
  --color-surface: #171a21;
  --color-surface-hover: #1e222b;
  --color-border: #262b35;
  --color-border-strong: #323844;

  --color-text: #e6e8ec;
  --color-text-secondary: #9aa1ad;
  --color-text-tertiary: #6b7280;

  --color-primary: #3b82f6;
  --color-primary-hover: #2f6fe0;
  --color-primary-soft: #16233f;

  --color-danger: #f87171;
  --color-danger-hover: #ef4444;
  --color-danger-soft: #2a1717;

  --color-divider: #23262f;
  --color-toast-bg: #e6e8ec;
  --color-toast-fg: #1a1d23;

  color-scheme: dark;
}