/* Subject hubs: keep navigation readable on narrow screens. */
@media (max-width: 600px) {
  .sh-topbar, .mh-topbar { flex-wrap: wrap; gap: 12px; }
  .sh-topbar nav, .mh-topbar nav { width: 100%; min-width: 0; }
  .sh-nav, .mh-nav { display: flex; flex-wrap: wrap; gap: 8px 16px; }
  .sh-nav a, .mh-nav a { display: inline-flex; min-height: 44px; align-items: center; }
}