@media (max-width: 900px) {
  .hero-grid, .exam-main { grid-template-columns: 1fr; }
  .exam-toolbar { flex-direction: column; align-items: flex-start; gap: 0.75rem; }
  .sidebar { position: static; }
}

@media (max-width: 620px) {
  main { padding: 1rem 0.8rem 2.5rem; }
  .hero { padding: 1.5rem; }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
}