/* ==========================================================================
   DESIGN TOKENS — Giáo trình Nhiếp ảnh Quốc tế
   ========================================================================== */

:root {
  /* ---------- COLORS (6 base + 2 semantic) ---------- */
  --bg: #FFFFFF;
  --surface: #F7F7F7;
  --text: #1A1A1A;
  --text-muted: #666666;
  --border: #E0E0E0;
  --primary: #0066CC;
  --primary-hover: #0052A3;
  --success: #1A7F37;
  --error: #CF222E;

  /* ---------- FONTS (2 families) ---------- */
  --font-body: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

  /* ---------- FONT SIZES (6 levels) ---------- */
  --fs-sm: 0.875rem;
  --fs-base: 1rem;
  --fs-lg: 1.125rem;
  --fs-xl: 1.25rem;
  --fs-2xl: 1.5rem;
  --fs-3xl: 2rem;

  /* ---------- FONT WEIGHTS (3 levels) ---------- */
  --fw-regular: 400;
  --fw-medium: 500;
  --fw-bold: 700;

  /* ---------- LINE HEIGHTS ---------- */
  --lh-body: 1.6;
  --lh-heading: 1.3;

  /* ---------- SPACING (6 levels) ---------- */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;

  /* ---------- RADIUS (2 levels) ---------- */
  --radius-sm: 4px;
  --radius-md: 6px;

  /* ---------- SHADOW (1 level) ---------- */
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);

  /* ---------- LAYOUT ---------- */
  --container: 1200px;
  --container-narrow: 800px;
  --header-height: 56px;

  /* ---------- TRANSITION ---------- */
  --transition: 0.15s ease;
}

[data-theme="dark"] {
  --bg: #0F0F0F;
  --surface: #1A1A1A;
  --text: #F0F0F0;
  --text-muted: #999999;
  --border: #2A2A2A;
  --primary: #4D9EFF;
  --primary-hover: #7AB5FF;
  --success: #3FB950;
  --error: #F85149;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}