/* App Layout */
.app-layout {
  display: flex;
  min-height: 100vh;
}

/* ─── Sidebar ─── */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  height: 100vh;
  width: var(--sidebar-width);
  background-color: var(--color-sidebar);
  display: flex;
  flex-direction: column;
  z-index: 100;
  transition: width var(--transition-base);
  overflow: hidden;
  flex-shrink: 0;
}

.sidebar.collapsed {
  width: var(--sidebar-collapsed);
}

/* Sidebar Header */
.sidebar-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-lg) var(--spacing-md);
  height: var(--topbar-height);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  flex-shrink: 0;
}

.sidebar-logo {
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: #fff;
  font-size: 18px;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}

.sidebar-brand-group {
  display: flex;
  flex-direction: column;
  gap: 0;
  overflow: hidden;
  opacity: 1;
  transition: opacity var(--transition-base);
}

.sidebar.collapsed .sidebar-brand-group {
  opacity: 0;
  width: 0;
  overflow: hidden;
}

.sidebar-brand {
  font-size: var(--font-size-md);
  font-weight: 700;
  color: #ffffff;
  white-space: nowrap;
}

.sidebar-version {
  font-size: 10px;
  color: rgba(161, 167, 179, 0.5);
  line-height: 1;
}

/* Sidebar Navigation */
.sidebar-nav {
  flex: 1;
  padding: var(--spacing-md) 0;
  overflow-y: auto;
  overflow-x: hidden;
}

.sidebar-nav::-webkit-scrollbar {
  width: 0;
}

.nav-section-label {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: rgba(161, 167, 179, 0.5);
  white-space: nowrap;
  opacity: 1;
  transition: opacity var(--transition-base);
}

.sidebar.collapsed .nav-section-label {
  opacity: 0;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: 10px var(--spacing-md);
  margin: 2px var(--spacing-sm);
  border-radius: var(--radius-md);
  color: var(--color-text-sidebar);
  text-decoration: none;
  transition: background-color var(--transition-fast), color var(--transition-fast);
  cursor: pointer;
  white-space: nowrap;
  position: relative;
}

.nav-item:hover {
  background-color: var(--color-sidebar-hover);
  color: #ffffff;
  text-decoration: none;
}

.nav-item.active {
  background-color: var(--color-sidebar-active);
  color: #ffffff;
}

.nav-item .material-icons {
  font-size: 20px;
  flex-shrink: 0;
  width: 20px;
}

.nav-item-label {
  font-size: var(--font-size-sm);
  font-weight: 500;
  opacity: 1;
  transition: opacity var(--transition-base);
  flex: 1;
}

.sidebar.collapsed .nav-item-label {
  opacity: 0;
  width: 0;
  overflow: hidden;
}

/* Tooltip on collapsed */
.sidebar.collapsed .nav-item:hover::after {
  content: attr(data-label);
  position: absolute;
  left: calc(var(--sidebar-collapsed) - 4px);
  top: 50%;
  transform: translateY(-50%);
  background: #2a2d35;
  color: #fff;
  font-size: var(--font-size-sm);
  font-weight: 500;
  padding: 6px 12px;
  border-radius: var(--radius-md);
  white-space: nowrap;
  z-index: 200;
  pointer-events: none;
  box-shadow: var(--shadow-lg);
}

/* Sidebar Footer */
.sidebar-footer {
  padding: var(--spacing-md);
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  flex-shrink: 0;
}

.sidebar-collapse-btn {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  width: 100%;
  padding: 10px var(--spacing-sm);
  border-radius: var(--radius-md);
  color: var(--color-text-sidebar);
  background: none;
  border: none;
  cursor: pointer;
  transition: background-color var(--transition-fast), color var(--transition-fast);
  white-space: nowrap;
}

.sidebar-collapse-btn:hover {
  background-color: var(--color-sidebar-hover);
  color: #ffffff;
}

.sidebar-collapse-btn .material-icons {
  font-size: 20px;
  flex-shrink: 0;
  transition: transform var(--transition-base);
}

.sidebar.collapsed .sidebar-collapse-btn .material-icons {
  transform: rotate(180deg);
}

.sidebar-collapse-btn .collapse-label {
  font-size: var(--font-size-sm);
  font-weight: 500;
  opacity: 1;
  transition: opacity var(--transition-base);
}

.sidebar.collapsed .sidebar-collapse-btn .collapse-label {
  opacity: 0;
  width: 0;
  overflow: hidden;
}

/* ─── Main Area ─── */
.main-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  transition: margin-left var(--transition-base);
}

.main-area.sidebar-collapsed {
  margin-left: var(--sidebar-collapsed);
}

/* ─── Topbar ─── */
.topbar {
  position: fixed;
  top: 0;
  right: 0;
  left: var(--sidebar-width);
  height: var(--topbar-height);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-lg);
  z-index: 90;
  transition: left var(--transition-base);
}

.topbar.sidebar-collapsed {
  left: var(--sidebar-collapsed);
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.topbar-hamburger {
  display: none;
  color: var(--color-text-secondary);
  padding: var(--spacing-xs);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.topbar-hamburger:hover {
  background-color: var(--color-border-light);
  color: var(--color-text);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.breadcrumb-item {
  color: var(--color-text-secondary);
}

.breadcrumb-item.active {
  color: var(--color-text);
  font-weight: 500;
}

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

.topbar-right {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

/* ─── Main Content ─── */
.main-content {
  flex: 1;
  margin-top: var(--topbar-height);
  padding: var(--spacing-lg);
  overflow-y: auto;
}

/* ─── Page Header ─── */
.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--color-border-light);
}

.page-header-left {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-title {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
}

.page-subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.page-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

/* ─── Stats Grid ─── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.content-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--spacing-md);
}

.content-grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-md);
}

.content-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-md);
}

/* ─── Overlay for mobile ─── */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 99;
  backdrop-filter: blur(2px);
}

.sidebar-overlay.active {
  display: block;
}