.app-shell {
  display: flex;
  min-height: 100vh;
  background: var(--content-bg);
}

.sidebar {
  width: var(--sidebar-width);
  background: var(--sidebar-bg);
  color: var(--sidebar-text);
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  display: flex;
  flex-direction: column;
  transition: var(--transition-base);
  z-index: 100;
  overflow: hidden;
}

.sidebar-logo {
  height: var(--topbar-height);
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 16px;
  background: var(--sidebar-logo-bg);
  color: var(--sidebar-text-active);
  flex-shrink: 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.sidebar-logo-icon {
  width: 22px;
  height: 22px;
  flex-shrink: 0;
}

.sidebar-logo-text {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.3px;
  white-space: nowrap;
  opacity: 1;
  transition: opacity 0.2s;
}

.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: 8px 0;
  display: flex;
  flex-direction: column;
}

.sidebar-nav::-webkit-scrollbar {
  width: 6px;
}

.sidebar-nav::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 20px;
  height: 50px;
  color: var(--sidebar-text);
  text-decoration: none;
  position: relative;
  transition: background 0.2s, color 0.2s;
  white-space: nowrap;
}

.nav-item:hover {
  background: var(--sidebar-bg-hover);
  color: var(--sidebar-text-active);
}

.nav-item.is-active {
  background: var(--sidebar-bg-dk);
  color: var(--sidebar-text-active);
}

.nav-item.is-active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--sidebar-active-marker);
}

.nav-icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.nav-text {
  font-size: 14px;
  flex: 1;
  opacity: 1;
  transition: opacity 0.2s;
}

.nav-divider {
  height: 1px;
  background: rgba(255, 255, 255, 0.06);
  margin: 12px 16px;
}

.nav-item-external {
  color: rgba(191, 203, 217, 0.7);
}

.nav-external {
  width: 12px;
  height: 12px;
  opacity: 0.6;
  flex-shrink: 0;
}

.main {
  flex: 1;
  margin-left: var(--sidebar-width);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: margin-left 0.28s cubic-bezier(0.645, 0.045, 0.355, 1);
}

.topbar {
  height: var(--topbar-height);
  background: var(--topbar-bg);
  border-bottom: 1px solid var(--topbar-border);
  box-shadow: var(--topbar-shadow);
  display: flex;
  align-items: center;
  padding: 0 20px;
  gap: 16px;
  position: sticky;
  top: 0;
  z-index: 50;
}

.topbar-toggle {
  width: 32px;
  height: 32px;
  border: none;
  background: transparent;
  color: var(--text-regular);
  cursor: pointer;
  border-radius: var(--radius-base);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  transition: background 0.2s;
}

.topbar-toggle:hover {
  background: var(--border-extra-light);
}

.topbar-toggle svg {
  width: 18px;
  height: 18px;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-secondary);
}

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

.breadcrumb-sep {
  color: var(--text-placeholder);
}

.topbar-spacer {
  flex: 1;
}

.topbar-user {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-regular);
}

.topbar-user-email {
  font-weight: 500;
}

.content {
  flex: 1;
  padding: 20px;
  background: var(--content-bg);
}

.content-loading {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-secondary);
}

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

.app-shell.is-collapsed .sidebar-logo-text,
.app-shell.is-collapsed .nav-text,
.app-shell.is-collapsed .nav-external {
  opacity: 0;
  pointer-events: none;
}

.app-shell.is-collapsed .nav-item,
.app-shell.is-collapsed .sidebar-logo {
  padding: 0 22px;
}

.app-shell.is-collapsed .main {
  margin-left: var(--sidebar-width-collapsed);
}

@media (max-width: 992px) {
  .sidebar {
    width: var(--sidebar-width-collapsed);
  }
  .sidebar-logo-text,
  .nav-text,
  .nav-external {
    opacity: 0;
    pointer-events: none;
  }
  .nav-item,
  .sidebar-logo {
    padding: 0 22px;
  }
  .main {
    margin-left: var(--sidebar-width-collapsed);
  }
}

@media (max-width: 600px) {
  .content {
    padding: 12px;
  }
  .breadcrumb-item:not(.is-current) {
    display: none;
  }
  .breadcrumb-sep {
    display: none;
  }
}