/* ==========================================================================
   About Panel Component
   Overrides and about-specific rules (base panel rules in panel.css)
   ========================================================================== */

.about-panel {
  max-height: 80vh;
  z-index: var(--z-drawer);
}

/* Lift above player bar when playing */
body[data-state="playing"] .about-panel {
  bottom: var(--player-height);
}

/* --------------------------------------------------------------------------
   Theme Button (left side of header)
   -------------------------------------------------------------------------- */

.about-panel__theme-btn {
  width: var(--touch-target);
  height: var(--touch-target);
  border: none;
  background: transparent;
  color: var(--color-text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  margin-left: calc(-1 * var(--space-2));
  transition: color var(--duration-fast) var(--ease-out),
              background var(--duration-fast) var(--ease-out);
}

.about-panel__theme-btn:hover,
.about-panel__theme-btn:focus-visible {
  color: var(--color-text);
  background: var(--color-surface-elevated);
}

.about-panel__theme-btn .icon {
  width: 20px;
  height: 20px;
}

/* --------------------------------------------------------------------------
   Content Area
   -------------------------------------------------------------------------- */

.about-panel__content {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.about-panel__text {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.6;
}

.about-panel__philosophy {
  font-style: italic;
  color: var(--color-text);
  font-size: var(--text-sm);
}

.about-panel__tech {
  font-size: var(--text-xs);
  color: var(--color-text-subtle);
  line-height: 1.6;
}

.about-panel__link {
  color: var(--color-text-muted);
  text-decoration: none;
  border-bottom: 1px solid var(--color-border);
  transition: color var(--duration-fast) var(--ease-out),
              border-color var(--duration-fast) var(--ease-out);
}

.about-panel__link:hover,
.about-panel__link:focus-visible {
  color: var(--color-text);
  border-color: var(--color-accent);
}

/* --------------------------------------------------------------------------
   Tabs
   -------------------------------------------------------------------------- */

.about-panel__tabs {
  display: flex;
  gap: var(--space-1);
}

.about-panel__tab {
  padding: var(--space-1) var(--space-3);
  border: none;
  background: transparent;
  color: var(--color-text-muted);
  font-size: var(--text-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: color var(--duration-fast) var(--ease-out),
              background var(--duration-fast) var(--ease-out);
}

.about-panel__tab:hover {
  color: var(--color-text);
}

.about-panel__tab--active {
  background: var(--color-surface-elevated);
  color: var(--color-text);
}

.about-panel__tab:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* --------------------------------------------------------------------------
   Body Wrapper (grid stack for tabpanel crossfade)
   Both tabpanels occupy the same grid cell so the panel height equals the
   tallest tab — no size jump when switching. Body is the scroll container.
   -------------------------------------------------------------------------- */

.about-panel__body {
  flex: 1;
  display: grid;
  min-height: 0;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
  padding-bottom: calc(var(--space-4) + env(safe-area-inset-bottom, 0));
}

.about-panel__body::-webkit-scrollbar {
  width: 4px;
}

.about-panel__body::-webkit-scrollbar-track {
  background: transparent;
}

.about-panel__body::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-full);
}

/* --------------------------------------------------------------------------
   Tabpanel Crossfade
   Grid stacking (both panels in 1/1) avoids position toggling which caused
   layout flash. aria-hidden allows opacity transition (hidden kills it).
   -------------------------------------------------------------------------- */

.about-panel__content[role="tabpanel"] {
  grid-area: 1 / 1;
}

.about-panel__content[role="tabpanel"][aria-hidden="true"] {
  opacity: 0;
  pointer-events: none;
  visibility: hidden;
  transition: opacity var(--duration-fast) var(--ease-out),
              visibility 0s var(--duration-fast);
}

.about-panel__content[role="tabpanel"][aria-hidden="false"] {
  opacity: 1;
  pointer-events: auto;
  visibility: visible;
  transition: opacity var(--duration-fast) var(--ease-out),
              visibility 0s 0s;
}

/* --------------------------------------------------------------------------
   Tab Content
   -------------------------------------------------------------------------- */

.about-panel__heading {
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-text);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-2);
}

.about-panel__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   Reduced Motion
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  .about-panel__theme-btn,
  .about-panel__close,
  .about-panel__link,
  .about-panel__tab {
    transition: none;
  }

  .about-panel__content[role="tabpanel"] {
    transition: none;
  }
}