/* =====================================================================
   SHARED SITE HEADER — slim top navigation bar
   Single source of truth for the persistent header across all apps.
   Pair with shared/header.js, which renders the markup.

   Styling adapts to each host page via CSS custom properties, with
   sensible fallbacks so the bar looks right even on a page that only
   defines some of them:
     --color-accent     bar background
     --color-text       button / label colour
     --color-charcoal   bottom border
     --border-width     bottom border thickness
     --font-data        button font family
   The host page is responsible only for positioning (margins), since
   that depends on its own body / container padding.
   ===================================================================== */
.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 16px;
  background: var(--color-accent, #9E2A2B);
  color: var(--color-text, #FFF3D1);
  border: none;
  border-bottom: var(--border-width, 3px) solid var(--color-charcoal, #212529);
  box-shadow: inset 0 0 0 3px var(--color-text, #FFF3D1);
  border-radius: 0;
  padding: 10px 18px;
}
.topbar-right {
  display: flex;
  align-items: center;
  gap: 16px;
}
.about-btn {
  font-family: var(--font-data, system-ui, -apple-system, sans-serif);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text, #FFF3D1);
  background: transparent;
  border: 2px solid rgba(255, 243, 209, 0.45);
  border-radius: 6px;
  padding: 4px 10px;
  cursor: pointer;
  white-space: nowrap;
  text-decoration: none;
  display: inline-block;
  transition: background 0.12s, border-color 0.12s;
}
.about-btn:hover {
  background: rgba(255, 243, 209, 0.12);
  border-color: var(--color-text, #FFF3D1);
}
.about-btn.is-active {
  background: var(--color-text, #FFF3D1);
  color: var(--color-accent, #9E2A2B);
  border-color: var(--color-text, #FFF3D1);
}

@media (max-width: 700px) {
  .topbar { flex-wrap: wrap; justify-content: center; text-align: center; gap: 8px; }
  .topbar-right { justify-content: center; }
}