/* Case-only chapter rail. The real header remains above it. */
.tc-page { --tc-header-offset: 3.125rem; --tc-chapter-height: 3.75rem; --tc-z-chapters: 40; }
.tc-page .tc-story-nav {
  position: sticky;
  top: var(--tc-header-offset);
  z-index: var(--tc-z-chapters);
  display: block;
  width: 100%;
  padding: .5rem max(var(--tc-container-gutter), calc((100% - var(--container-8xl)) / 2 + var(--tc-container-gutter)));
  margin-top: 1.5rem;
  border-block: 1px solid var(--tc-rule);
  background: var(--tc-paper);
}
.tc-chapter-links { display: flex; flex-wrap: wrap; gap: .5rem; }
.tc-story-nav a { white-space: nowrap; border-color: transparent; }
.tc-story-nav a[aria-current="location"] { background: var(--tc-ink); color: var(--tc-paper); }
.tc-chapter-picker { display: none; }
.tc-page [id]:not(.tc-cover-sr-only) { scroll-margin-top: calc(var(--tc-header-offset) + var(--tc-chapter-height) + 1rem); }
@media (max-width: 47.99rem) {
  .tc-story-nav[data-enhanced] .tc-chapter-links { display: none; }
  .tc-story-nav[data-enhanced] .tc-chapter-picker { display: flex; align-items: center; gap: 1rem; }
  .tc-chapter-picker > label { flex-shrink: 0; font: .75rem/1.4 var(--font-mono), monospace; color: var(--tc-quiet); }
  .tc-chapter-picker > select { flex: 1; min-width: 0; min-height: 2.75rem; padding: .625rem .75rem; border: 1px solid var(--tc-rule); background: var(--tc-paper); color: var(--tc-ink); font: .875rem/1.4 var(--font-sans), sans-serif; }
  .tc-chapter-picker > select:focus-visible { outline: 2px solid var(--tc-focus); outline-offset: 2px; }
}
@media (min-width: 49.75rem) {
  .tc-page { --tc-header-offset: 4rem; }
}
@media (prefers-reduced-motion: reduce) {
  html:has(.tc-page) { scroll-behavior: auto; }
}