.return-room-link {
  color: inherit;
  text-decoration: none;
}

.return-room-link:hover,
.return-room-link:focus-visible {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.return-room-link:focus-visible { outline: 2px solid currentColor; outline-offset: 4px; }

.placeholder-return {
  display: inline-block;
  margin-top: 18px;
  color: inherit;
  font-size: 0.92rem;
}

/* Shared topic-page navigation: each page keeps its own palette through currentColor. */
.site-wordmark.room-return-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: Inter, "Noto Sans SC", "Microsoft YaHei", sans-serif;
  font-size: 0.84rem;
  font-style: normal;
  letter-spacing: 0.035em;
}

.site-wordmark.room-return-link::before {
  content: "\2190";
  font-size: 1.1rem;
  line-height: 1;
}

.site-wordmark.room-return-link::after { display: none; }

.main-nav .interest-nav-group,
.site-nav .interest-nav-group {
  position: relative;
  display: flex;
  align-items: center;
}

.main-nav .interest-menu-toggle,
.site-nav .interest-menu-toggle {
  display: inline-flex;
  align-items: center;
  padding: 0;
  border: 0;
  background: transparent;
  color: inherit;
  cursor: pointer;
  font: inherit;
}

.main-nav .interest-menu-toggle::after,
.site-nav .interest-menu-toggle::after {
  display: inline-block;
  margin-left: 6px;
  content: "\2304";
  font-size: 0.72em;
  transition: transform 160ms ease;
}

.main-nav .interest-menu-toggle:hover,
.main-nav .interest-menu-toggle.active,
.site-nav .interest-menu-toggle:hover,
.site-nav .interest-menu-toggle.active { color: currentColor; }

.main-nav .interest-nav-group.submenu-open .interest-menu-toggle::after,
.site-nav .interest-nav-group.submenu-open .interest-menu-toggle::after { transform: rotate(180deg); }

.main-nav .interest-menu,
.site-nav .interest-menu {
  display: none;
  grid-template-columns: repeat(2, minmax(86px, 1fr));
  min-width: 218px;
  gap: 3px;
}

.main-nav .interest-nav-group:not(.submenu-open) .interest-menu,
.site-nav .interest-nav-group:not(.submenu-open) .interest-menu {
  display: none !important;
  visibility: hidden !important;
  opacity: 0 !important;
  pointer-events: none;
}

.main-nav .interest-nav-group.submenu-open .interest-menu,
.site-nav .interest-nav-group.submenu-open .interest-menu {
  display: grid;
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 780px) {
  .site-wordmark.room-return-link { font-size: 0.76rem; }

  .main-nav .interest-nav-group,
  .site-nav .interest-nav-group { display: block; }

  .main-nav .interest-menu-toggle,
  .site-nav .interest-menu-toggle {
    width: 100%;
    padding: 10px 0;
    text-align: left;
  }

  .main-nav .interest-menu,
  .site-nav .interest-menu,
  .main-nav .interest-nav-group.submenu-open .interest-menu,
  .site-nav .interest-nav-group.submenu-open .interest-menu {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    min-width: 0;
    padding: 0 0 8px;
    border: 0;
    background: transparent;
    box-shadow: none;
    visibility: visible;
    opacity: 1;
    transform: none;
  }

  .main-nav .interest-nav-group:not(.submenu-open) .interest-menu,
  .site-nav .interest-nav-group:not(.submenu-open) .interest-menu {
    display: grid !important;
    visibility: visible !important;
    opacity: 1 !important;
    pointer-events: auto;
  }
}