:root {
  /* Brand: education + AI + friendly, contrast >= 4.5:1 */
  --brand-900: #0c2e3e;
  --brand-800: #134e5e;
  --brand-700: #0f766e;
  --brand-600: #0d9488;
  --brand-100: #ccfbf1;
  --brand-50: #f0fdfa;
  --accent-600: #b45309;
  --accent-500: #d97706;
  --accent-100: #fef3c7;
  --ink-900: #1c1917;
  --ink-700: #44403c;
  --ink-500: #78716c;
  --paper: #fffbeb;
  --card: #ffffff;
  --line: #e7e5e4;
  --ok: #15803d;
  --err: #b91c1c;
  --radius: 16px;
  --shadow: 0 8px 24px rgba(12, 46, 62, 0.12);
  --shadow-lg: 0 16px 40px rgba(12, 46, 62, 0.18);
  --hero-grad: linear-gradient(180deg, #f0fdfa 0%, #fffbeb 70%);
  --accent-grad: linear-gradient(135deg, #d97706 0%, #b45309 100%);
  --font-ui: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-head: "Plus Jakarta Sans", "Inter", system-ui, sans-serif;
}

* { box-sizing: border-box; }