.app-layout {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: var(--sidebar-width);
  background-color: var(--bg-primary);
  border-right: 1px solid var(--border-primary);
  display: flex;
  flex-direction: column;
  transition: width var(--transition-normal);
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 100;
}

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

.sidebar-header {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--border-primary);
  height: var(--header-height);
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
}

.sidebar.collapsed .sidebar-brand-text {
  display: none;
}

.main-area {
  flex: 1;
  margin-left: var(--sidebar-width);
  transition: margin-left var(--transition-normal);
}

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

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-xl);
  height: var(--header-height);
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-primary);
  position: sticky;
  top: 0;
  z-index: 50;
}

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

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

.content-area {
  padding: var(--spacing-xl);
  min-height: calc(100vh - var(--header-height));
}

.page-header {
  margin-bottom: var(--spacing-xl);
}

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

.page-description {
  font-size: var(--font-size-md);
  color: var(--text-secondary);
}

@media screen and (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    width: var(--sidebar-width);
    z-index: 1000;
  }

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

  .sidebar.collapsed {
    width: var(--sidebar-width);
    transform: translateX(-100%);
  }

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

  .main-area {
    margin-left: 0 !important;
  }

  .topbar {
    padding: 0 var(--spacing-md);
  }

  .content-area {
    padding: var(--spacing-md);
  }

  .mobile-overlay {
    position: fixed;
    inset: 0;
    background: var(--bg-overlay);
    z-index: 999;
    display: none;
  }

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

@media screen and (min-width: 769px) and (max-width: 1024px) {
  .sidebar {
    width: var(--sidebar-collapsed-width);
  }

  .sidebar .sidebar-brand-text,
  .sidebar .nav-item-text,
  .sidebar .nav-expand-icon {
    display: none;
  }

  .sidebar .nav-submenu {
    position: fixed;
    left: var(--sidebar-collapsed-width);
    top: 0;
    bottom: 0;
    width: 200px;
    background: var(--bg-primary);
    border-right: 1px solid var(--border-primary);
    z-index: 200;
    max-height: 100vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
  }

  .nav-section:hover > .nav-submenu,
  .nav-section.expanded > .nav-submenu {
    display: block !important;
  }

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