/* ============================================================
   Layout — App Shell, Sidebar + Content Grid
   ============================================================ */

/* 초기 로드 중 모든 transition/animation 차단 — FOUC 및
   저장된 sidebar width/collapsed 상태 복원 시의 플래시 방지 */
html.preload *,
html.preload *::before,
html.preload *::after {
  transition: none !important;
  animation-duration: 0s !important;
  animation-delay: 0s !important;
}

/* ── App Shell ── */
.app-shell {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ── Topbar ── */
.topbar {
  height: var(--topbar-height);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 0 var(--space-4);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-xs);
  position: relative;
  z-index: var(--z-sticky);
  flex-shrink: 0;
}

.topbar-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-lg);
  font-weight: var(--weight-bold);
  color: var(--color-text);
  text-decoration: none;
}
.topbar-logo:hover { text-decoration: none; color: var(--color-primary-600); }

.topbar-logo-icon {
  width: 28px;
  height: 28px;
  background: var(--color-primary-600);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  flex-shrink: 0;
}

.topbar-search {
  flex: 1;
  max-width: 440px;
  margin-left: auto;
  margin-right: auto;
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

/* ── Main Area (sidebar + content) ── */
.main-area {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ── Sidebar ── */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-min);
  max-width: var(--sidebar-max);
  height: 100%;
  display: flex;
  flex-direction: column;
  background: var(--color-bg-sidebar);
  border-right: 1px solid var(--color-border);
  overflow: hidden;
  flex-shrink: 0;
  transition: width var(--transition-slow), opacity var(--transition-slow);
}

.sidebar.collapsed {
  width: 0 !important;
  min-width: 0;
  opacity: 0;
  pointer-events: none;
}

.sidebar-header {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sidebar-header-title {
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.sidebar-scroll {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-2) 0;
}

/* ── Resize Handle ── */
.resize-handle {
  width: var(--resize-handle-w);
  background: transparent;
  cursor: col-resize;
  flex-shrink: 0;
  position: relative;
  transition: background var(--transition-base);
}

.resize-handle::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 1px;
  background: var(--color-border);
  transition: background var(--transition-base), width var(--transition-base);
}

.resize-handle:hover::after,
.resize-handle.dragging::after {
  width: 3px;
  background: var(--color-primary-400);
}

/* ── Content Area ── */
.content-area {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  overscroll-behavior: contain; /* 스크롤 체이닝/바운스 차단 */
}

.content-inner {
  max-width: var(--content-max);
  width: 100%;
  margin: 0 auto;
  padding: var(--space-8) var(--space-8) var(--space-10);
}

/* (toggle button moved to sidebar header and topbar — see sidebar.css) */

/* ── Home Grid Layout ── */
.class-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-5);
  margin-top: var(--space-6);
}

/* ── Page Header ── */
.page-header {
  margin-bottom: var(--space-8);
}

.page-title {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.page-subtitle {
  font-size: var(--text-base);
  color: var(--color-text-muted);
}

/* ── Breadcrumb ── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--color-text-muted);
  text-decoration: none;
}
.breadcrumb a:hover { color: var(--color-primary-600); }

.breadcrumb-sep {
  color: var(--color-gray-500);
  font-size: var(--text-xs);
}

.breadcrumb-current {
  color: var(--color-text);
  font-weight: var(--weight-medium);
}

/* ── Function List ── */
.function-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.function-list-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: var(--color-text);
  transition: var(--transition-colors), box-shadow var(--transition-base),
              transform var(--transition-fast);
}

.function-list-item:hover {
  background: var(--color-bg-hover);
  border-color: var(--color-primary-200);
  box-shadow: var(--shadow-sm);
  transform: translateX(2px);
  text-decoration: none;
  color: var(--color-primary-700);
}

.function-list-item-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-md);
  background: var(--color-primary-100);
  color: var(--color-primary-600);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xs);
  font-weight: var(--weight-bold);
  font-family: var(--font-mono);
  flex-shrink: 0;
}

.function-list-item-name {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
}

/* ── Floating Action Button (Source) ── */
.fab {
  position: fixed;
  bottom: var(--space-8);
  right: var(--space-8);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  background: var(--color-primary-600);
  color: var(--color-text-inverse);
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-lg);
  font-size: var(--text-sm);
  font-weight: var(--weight-medium);
  cursor: pointer;
  border: none;
  z-index: var(--z-above);
  transition: background var(--transition-base), box-shadow var(--transition-base),
              transform var(--transition-fast);
}

.fab:hover {
  background: var(--color-primary-700);
  box-shadow: var(--shadow-xl);
  transform: translateY(-2px);
}

.fab:active { transform: translateY(0); }

/* ── Empty State ── */
.empty-state {
  text-align: center;
  padding: var(--space-16) var(--space-8);
  color: var(--color-text-muted);
}

.empty-state-icon {
  font-size: 3rem;
  margin-bottom: var(--space-4);
  opacity: 0.4;
}

.empty-state-title {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.empty-state-desc {
  font-size: var(--text-sm);
  max-width: 360px;
  margin: 0 auto;
}

/* ============================================================
   Responsive
   ============================================================ */

@media (max-width: 1024px) {
  .sidebar {
    width: 240px;
  }
  .content-inner {
    padding: var(--space-6);
  }
}

@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    top: var(--topbar-height);
    left: 0;
    height: calc(100vh - var(--topbar-height));
    z-index: var(--z-modal);
    box-shadow: var(--shadow-xl);
    width: 280px !important;
    transform: translateX(-100%);
    transition: transform var(--transition-slow);
  }

  .sidebar.mobile-open {
    transform: translateX(0);
  }

  .sidebar.collapsed {
    transform: translateX(-100%);
    width: 280px !important;
    opacity: 1;
    pointer-events: auto;
  }

  .sidebar-overlay {
    display: block;
    position: fixed;
    inset: 0;
    background: var(--color-bg-overlay);
    z-index: calc(var(--z-modal) - 1);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-slow);
  }

  .sidebar-overlay.active {
    opacity: 1;
    pointer-events: auto;
  }

  .resize-handle { display: none; }

  .content-inner { padding: var(--space-4); }

  .class-grid { grid-template-columns: 1fr; }

  .fab {
    bottom: var(--space-5);
    right: var(--space-4);
    padding: var(--space-3) var(--space-4);
  }

  .page-title { font-size: var(--text-2xl); }
}