:root {
  --ets-navy: #1b2a4a;
  --ets-dark: #0f1724;
  --ets-blue: #2b5797;
  --ets-light-blue: #4a90d9;
  --ets-header: #1e3a5f;
  --ets-sidebar: #f5f6f8;
  --ets-text: #2c3e50;
  --ets-border: #d1d5db;
  --ets-correct: #059669;
  --ets-wrong: #dc2626;
  --ets-highlight: #fef08a;
  /* theme */
  --bg-body: #f0f2f5;
  --bg-surface: #ffffff;
  --bg-surface-2: #fafbfc;
  --bg-surface-3: #f8fafc;
  --bg-muted: #f1f5f9;
  --text-primary: #1a1a1a;
  --text-muted: #6b7280;
  --border-light: #e5e7eb;
  --border-medium: #d1d5db;
  --choice-hover: #eff6ff;
  --choice-sel: #dbeafe;
  --btn-bar-bg: #e5e7eb;
  --heading-color: #1e3a5f;
  /* semantic */
  --success-bg: #d1fae5;
  --success-text: #059669;
  --error-bg: #fee2e2;
  --error-text: #dc2626;
  --info-bg: #eff6ff;
  --info-text: #1d4ed8;
  --info-border: #bfdbfe;
  --warning-bg: #fef9c3;
  --warning-text: #a16207;
  --warning-border: #fde68a;
  --progress-track: #e5e7eb;
  --code-bg: #f1f5f9;
  --code-border: #e2e8f0;
  --figure-bg: #f8fafc;
  --link-text: #4338ca;
  --sel-bg: #dbeafe;
  --sel-border: #3b82f6;
  --sel-hover-bg: #bfdbfe;
}

[data-theme="dark"] {
  --ets-blue: #4a90d9;
  --ets-light-blue: #60a5fa;
  --ets-text: #e2e8f0;
  --ets-border: #374151;
  --ets-correct: #34d399;
  --ets-wrong: #f87171;
  --ets-highlight: #78350f;
  --bg-body: #0d1117;
  --bg-surface: #161b27;
  --bg-surface-2: #1a2030;
  --bg-surface-3: #1e2538;
  --bg-muted: #1e2538;
  --text-primary: #e2e8f0;
  --text-muted: #94a3b8;
  --border-light: #2d3748;
  --border-medium: #374151;
  --choice-hover: #1e3358;
  --choice-sel: #1e3a60;
  --btn-bar-bg: #1e2538;
  --heading-color: #93c5fd;
  /* semantic dark overrides */
  --success-bg: #064e3b;
  --success-text: #34d399;
  --error-bg: #450a0a;
  --error-text: #f87171;
  --info-bg: #1e2d4a;
  --info-text: #93c5fd;
  --info-border: #2d5986;
  --warning-bg: #3d2500;
  --warning-text: #fbbf24;
  --warning-border: #854d0e;
  --progress-track: #374151;
  --code-bg: #1e2538;
  --code-border: #2d3748;
  --figure-bg: #1a2030;
  --link-text: #93c5fd;
  --sel-bg: #1e3a60;
  --sel-border: #60a5fa;
  --sel-hover-bg: #1e3060;
}