/* ==========================================================================
   animations.css
   Restrained, purposeful motion only. No page-level transitions, no
   scroll-driven animation, no gradients. The global prefers-reduced-motion
   override already lives in base.css and applies to everything below —
   it is not duplicated here.

   Phase 7.2 status:
     - §2 (folder expand/collapse) is DORMANT. The flat tree no longer
       renders .folder-tree__branch or .folder-tree__toggle, so these
       rules match nothing. Kept per Phase 7.2 guardrail (cannot verify
       base.css / utilities.css / styles.css don't reference them).
     - §7 (sidebar width transition) is unchanged and still active.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. THEME TRANSITION
   -------------------------------------------------------------------------- */
.explorer-sidebar,
.explorer-toolbar,
.explorer-main,
.card,
.drive-shell,
.drive-topbar,
.drive-tabs,
.drive-card,
.drive-bottom-nav,
.drive-drawer__panel {
  transition: background-color var(--transition-theme), border-color var(--transition-theme), box-shadow var(--transition-theme);
}

/* --------------------------------------------------------------------------
   2. FOLDER EXPAND / COLLAPSE — DORMANT (Phase 7.2)
   The flat sidebar no longer renders .folder-tree__branch or
   .folder-tree__toggle, so none of the rules below match. Kept in place
   pending a cleanup pass with full grep access to base.css / utilities.css
   / styles.css. Removing a class reference without that verification is
   exactly the Phase 4 mistake the guardrail exists to prevent.
   -------------------------------------------------------------------------- */
.folder-tree__branch {
  max-height: 480px;
  opacity: 1;
  overflow: hidden;
  transition: max-height var(--transition-base), opacity var(--transition-fast);
}

.folder-tree__branch.is-collapsed {
  max-height: 0;
  opacity: 0;
}

.folder-tree__toggle[aria-expanded="true"] .folder-tree__icon {
  transform: rotate(0deg);
}

.folder-tree__toggle[aria-expanded="false"] .folder-tree__icon {
  transform: rotate(-90deg);
}

/* --------------------------------------------------------------------------
   3. HOVER TRANSITIONS
   .folder-tree__toggle is DORMANT in the flat tree — left in the shared
   selector per Phase 7.2 guardrail.
   -------------------------------------------------------------------------- */
.card,
.drive-card {
  will-change: transform;
}

.folder-tree__toggle,
.folder-tree__leaf,
.drive-drawer__link,
.drive-bottom-nav__item,
.drive-tabs__tab,
.filter-chip {
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

/* --------------------------------------------------------------------------
   4. FOCUS RING TRANSITION
   -------------------------------------------------------------------------- */
a,
button,
input,
[tabindex] {
  transition: outline-offset var(--transition-fast);
}

/* --------------------------------------------------------------------------
   5. DRAWER SLIDE-IN
   -------------------------------------------------------------------------- */
.drive-drawer__panel {
  transform: translateX(-100%);
  transition: transform var(--transition-base);
}

.drive-drawer__backdrop {
  opacity: 0;
  transition: opacity var(--transition-base);
}

.drive-drawer.is-open .drive-drawer__panel {
  transform: translateX(0);
}

.drive-drawer.is-open .drive-drawer__backdrop {
  opacity: 1;
}

/* --------------------------------------------------------------------------
   6. FAB — small entrance affordance
   -------------------------------------------------------------------------- */
@keyframes fab-settle {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.fab {
  animation: fab-settle var(--transition-base) ease-out;
}

/* --------------------------------------------------------------------------
   7. SIDEBAR COLLAPSE WIDTH TRANSITION (Phase 6, unchanged)
   -------------------------------------------------------------------------- */
.explorer-shell {
  transition: grid-template-columns var(--transition-base);
}

@media (prefers-reduced-motion: reduce) {
  .explorer-shell {
    transition: none;
  }
}