@media (max-width: 980px) {
  .sidebar {
    position: static;
    width: auto;
  }

  main {
    margin-left: 0;
    padding: 18px;
  }

  .topbar,
  .portal-hero,
  .grid-two,
  .auth-panel,
  .ontology-map {
    grid-template-columns: 1fr;
    display: grid;
  }

  .metrics {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}