.topic-browser {
  --tb-text: #2D3748; --tb-soft: #526072; --tb-bg: #FFFFFF;
  --tb-hover: #F7FAFC; --tb-line: #CBD5E1; --tb-accent: #326C8E;
  color: var(--tb-text);
}
[data-theme="dark"] .topic-browser {
  --tb-text: #E2E8F0; --tb-soft: #B8C2CE; --tb-bg: #1A2029;
  --tb-hover: #242D3A; --tb-line: #465569; --tb-accent: #87D1E8;
}
.topic-browser [hidden], #sitemap-source[hidden] { display: none !important; }
.topic-browser__controls { display: flex; flex-wrap: wrap; align-items: end; gap: 12px; }
.topic-browser__controls label { display: grid; gap: 6px; font-weight: 600; font-size: 14px; }
.topic-browser__search { flex: 1 1 240px; min-width: 0; }
.topic-browser__controls input, .topic-browser__controls select {
  width: 100%; min-height: 44px; border: 1px solid var(--tb-line); border-radius: 8px;
  padding: 9px 12px; background: var(--tb-bg); color: var(--tb-text); font: inherit;
}
.topic-browser__controls input::placeholder { color: var(--tb-soft); font-weight: 400; opacity: 1; }
.topic-browser__controls select { max-width: 100%; }
.topic-browser__controls label:not(.topic-browser__search) { flex: 1 1 220px; min-width: 0; }
.topic-browser__reset {
  min-height: 44px; border: 0; border-radius: 6px; background: var(--tb-hover);
  padding: 8px 12px; color: var(--tb-accent); font: inherit; cursor: pointer;
}
.topic-browser__status { margin: 16px 0; font-size: 14px; color: var(--tb-soft); }
.topic-browser__grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; align-items: start; }
.topic-browser__card { border: 1px solid var(--tb-line); border-radius: 12px; background: var(--tb-bg); overflow: clip; scroll-margin-top: 84px; }
.main-content .topic-browser__card > summary {
  display: grid; grid-template-columns: 1fr auto; align-items: start; gap: 8px 12px;
  min-height: 132px; padding: 18px 40px 18px 18px; position: relative;
  cursor: pointer; color: var(--tb-text); list-style: none;
}
.topic-browser__card > summary::-webkit-details-marker { display: none; }
.topic-browser__card > summary::after {
  content: '+'; position: absolute; right: 15px; top: 15px;
  font-size: 22px; color: var(--tb-accent); line-height: 1;
}
.topic-browser__card[open] > summary::after { content: '−'; }
.topic-browser__title { font-family: Inter, sans-serif; font-weight: 600; font-size: 16px; line-height: 1.4; }
.topic-browser__count { color: var(--tb-soft); white-space: nowrap; font-size: 12px; padding-top: 3px; }
.topic-browser__preview { grid-column: 1 / -1; color: var(--tb-soft); font-size: 13px; line-height: 1.5; }
.topic-browser__card[open] { grid-column: 1 / -1; }
.topic-browser__card[open] .topic-browser__pages { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
.topic-browser__card[open] > summary { min-height: 0; border-bottom: 1px solid var(--tb-line); }
.main-content .topic-browser__pages { list-style: none; margin: 0; padding: 8px; }
.main-content .topic-browser__pages > li { margin: 0; padding: 0; }
.main-content .topic-browser__pages > li::before { display: none; }
.topic-browser__pages a { display: block; padding: 10px; border-radius: 6px; color: var(--tb-accent); font-weight: 600; line-height: 1.4; }
.topic-browser__description { display: block; margin-top: 4px; color: var(--tb-soft); font-size: 13px; font-weight: 400; }
.topic-browser__pages a:hover, .topic-browser__pages a:focus-visible, .topic-browser__card > summary:hover { background: var(--tb-hover); }
.topic-browser :is(a, button, input, select, summary):focus-visible { outline: 2px solid var(--tb-accent); outline-offset: -3px; }
.topic-browser__empty { padding: 24px; border: 1px dashed var(--tb-line); border-radius: 12px; }
.topic-browser__notes { margin-top: 24px; color: var(--tb-soft); }
.topic-browser__notes > summary { cursor: pointer; min-height: 44px; padding: 10px 0; color: var(--tb-text); }
@media (prefers-reduced-motion: no-preference) {
  .topic-browser__card { transition: border-color .18s ease, box-shadow .18s ease; }
  .topic-browser__card:hover { border-color: var(--tb-accent); box-shadow: 0 3px 12px #0000000a; }
}
@media (max-width: 640px) {
  .topic-browser__grid, .topic-browser__card[open] .topic-browser__pages { grid-template-columns: minmax(0, 1fr); }
  .main-content .topic-browser__card > summary { min-height: 104px; }
}
@media print {
  .topic-browser { display: none; }
  #sitemap-source[hidden] { display: block !important; }
}

.topic-browser__subheading { display: block; margin-top: 3px; font-size: 12px; font-weight: 600; color: var(--tb-soft); }