/* HistoryBroom-authored, not vendored from Fernglas (see fernglas/VENDORED.md)
   - base.css only sets scrollbar-color, it has no thin/overlay/hover-widen
   scrollbar pattern to reuse. Built locally on Fernglas's semantic tokens
   per SKILL.md's "genuinely doesn't have it" case. Flag as a Fernglas
   backport candidate if another project wants this.

   ponytail: WebKit-only (::-webkit-scrollbar), fine since every consumer is
   Chromium. Thin-by-default + widen-on-hover is real, native, zero JS - but
   the track width is still reserved layout space, not a true zero-footprint
   JS-driven overlay thumb. Upgrade to a custom draggable thumb widget only
   if that reserved 4-8px ever actually matters. */
.scroll-overlay {
  overflow-y: auto;
  /* Standards-track fallback for the rendering path where the composited
     ::-webkit-scrollbar customization below doesn't apply (observed in a
     software-rendering/no-GPU-compositing Chromium instance during
     verification) - only 3 keyword widths exist here, no arbitrary px and
     no hover transition, but it's a real width change so it still degrades
     to something rather than the full-width classic scrollbar. */
  scrollbar-width: thin;
}
.scroll-overlay:hover {
  scrollbar-width: auto;
}
.scroll-overlay::-webkit-scrollbar {
  width: 4px;
  transition: width 0.15s ease;
}
.scroll-overlay:hover::-webkit-scrollbar {
  width: 8px;
}
.scroll-overlay::-webkit-scrollbar-track {
  background: transparent;
}
.scroll-overlay::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: 999px;
}
.scroll-overlay::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}