.desktop-navigation {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 6px;
  padding: 8px clamp(16px, 3vw, 40px);
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface) 94%, transparent);
  position: sticky;
  top: 0;
  z-index: 25;
}

.desk-nav-primary {
  position: relative;
  min-width: 0;
}

button.desk-nav-primary,
.desk-nav-primary > summary {
  display: flex;
  min-height: 44px;
  width: 100%;
  align-items: center;
  justify-content: center;
  border: 0;
  border-radius: 10px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font: inherit;
  font-weight: 700;
  list-style: none;
}

.desk-nav-primary > summary::-webkit-details-marker { display: none; }
.desk-nav-primary.is-active > summary,
button.desk-nav-primary.is-active {
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.desk-nav-menu {
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  z-index: 35;
  display: grid;
  min-width: 210px;
  gap: 3px;
  padding: 8px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  box-shadow: 0 16px 40px rgb(24 44 55 / 16%);
}

.desk-nav-child,
.mobile-sheet-item,
.utility-nav-item {
  min-height: 44px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--text);
  cursor: pointer;
  font: inherit;
  text-align: left;
  padding: 10px 12px;
}

.desk-nav-child:hover,
.desk-nav-child.is-active,
.mobile-sheet-item:hover,
.mobile-sheet-item.is-active,
.utility-nav-item:hover,
.utility-nav-item.is-active { background: var(--accent-soft); }

.mobile-bottom-navigation,
.mobile-materials-sheet { display: none; }

.utility-navigation { display: none; }

#viewHeading { scroll-margin-top: 72px; }

button:focus-visible,
summary:focus-visible,
input:focus-visible,
a:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--accent) 62%, white);
  outline-offset: 2px;
}

@media (min-width: 760px) {
  .control-panel {
    position: relative;
    top: auto;
    z-index: 4;
    margin-bottom: 10px;
  }

  .control-panel .search-box { max-width: 560px; }
}

@media (max-width: 759px) {
  body { padding-bottom: calc(66px + env(safe-area-inset-bottom)); }
  body.has-mobile-menu-open { overflow: hidden; }
  .desktop-navigation { display: none; }
  #viewHeading { scroll-margin-top: 76px; }

  .mobile-bottom-navigation {
    position: fixed;
    inset: auto 0 0;
    z-index: 60;
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 2px;
    padding: 6px 6px calc(6px + env(safe-area-inset-bottom));
    border-top: 1px solid var(--line);
    background: color-mix(in srgb, var(--surface) 96%, transparent);
    box-shadow: 0 -8px 28px rgb(24 44 55 / 12%);
  }

  .mobile-nav-item {
    min-width: 0;
    min-height: 48px;
    border: 0;
    border-radius: 10px;
    background: transparent;
    color: var(--muted);
    font: inherit;
    font-size: 12px;
    font-weight: 700;
  }

  .mobile-nav-item.is-active {
    background: var(--accent-soft);
    color: var(--accent-strong);
  }

  .mobile-materials-sheet {
    position: fixed;
    inset: auto 8px calc(68px + env(safe-area-inset-bottom));
    z-index: 65;
    display: block;
    max-height: min(65vh, 520px);
    overflow: auto;
    padding: 10px;
    border: 1px solid var(--line);
    border-radius: 16px;
    background: var(--surface);
    box-shadow: 0 18px 50px rgb(24 44 55 / 24%);
  }

  .mobile-materials-sheet[hidden] { display: none; }
  .mobile-materials-sheet header { display: flex; align-items: center; justify-content: space-between; padding: 4px 4px 8px; }
  .mobile-materials-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 4px; }
  .mobile-sheet-item { width: 100%; overflow-wrap: anywhere; }

  .control-panel { margin: 0; }
  .control-panel .search-box { max-width: none; }
  .utility-navigation { display: grid; gap: 12px; }
  .utility-navigation section { display: grid; gap: 4px; }
  .utility-navigation h2 { margin: 0 0 2px; color: var(--muted); font-size: 12px; }
  .utility-nav-item { width: 100%; }
}

@media (max-width: 420px) {
  .mobile-nav-item { font-size: 11px; }
  .mobile-materials-list { grid-template-columns: 1fr; }
}