@media (max-width: 1020px) {
  /* Keep navigation above every chat surface (90/95), including its inner-page stacking context. */
  header.site.x-hdr,
  .x-shell.x-inner { z-index: 96; }
  header.site.x-hdr.x-stuck {
    z-index: 96;
    animation: none;
    translate: 0 0;
    transition: translate 180ms ease;
  }
  header.site.x-hdr.x-stuck.x-scroll-hidden:not(.open) {
    translate: 0 calc(-100% - 24px);
    pointer-events: none;
  }
}
@media (prefers-reduced-motion: reduce) {
  header.site.x-hdr.x-stuck { transition: none; }
}