@media (max-width: 900px) {
  .site-header .inner { position: relative; }
  .nav.is-open {
    display: flex;
    position: absolute;
    top: 82px;
    left: 0;
    right: 0;
    z-index: 10;
    flex-direction: column;
    gap: 0;
    padding: 12px 16px;
    background: rgba(13, 30, 24, .98);
    border: 1px solid rgba(255, 255, 255, .2);
    box-shadow: 0 12px 28px rgba(0, 0, 0, .18);
  }
  .nav.is-open a {
    padding: 11px 0;
    border-bottom: 1px solid rgba(255, 255, 255, .14);
  }
  .nav.is-open a:last-child { border-bottom: 0; }
}