/* ============================================================
   layout.css — 整体布局：侧边栏 + 顶栏 + 内容区
   依赖：design-tokens.css
   ============================================================ */

/* ── 应用根布局 ─────────────────────────────────────── */
.app-layout {
  display: flex;
  min-height: 100vh;
}

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

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

/* 侧边栏 Logo 区 */
.sidebar-brand {
  padding: var(--space-5) var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  border-bottom: 1px solid rgba(255,255,255,0.06);
  min-height: var(--header-height);
  flex-shrink: 0;
}

.sidebar-logo {
  width: 36px; height: 36px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  flex-shrink: 0;
  box-shadow: 0 4px 12px rgba(255,107,107,0.4);
}

.sidebar-brand-text {
  overflow: hidden;
  transition: opacity var(--transition-base), width var(--transition-base);
}

.sidebar-brand-name {
  font-family: var(--font-display);
  font-size: var(--text-base);
  color: var(--color-white);
  font-weight: var(--font-regular);
  white-space: nowrap;
  line-height: 1.3;
}

.sidebar-brand-sub {
  font-size: var(--text-xs);
  color: rgba(255,255,255,0.45);
  white-space: nowrap;
}

.sidebar.collapsed .sidebar-brand-text { opacity: 0; width: 0; }

/* 班级切换器 */
.class-switcher {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid rgba(255,255,255,0.06);
  flex-shrink: 0;
}

.class-switcher select {
  width: 100%;
  background: rgba(255,255,255,0.08);
  color: var(--color-white);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius-md);
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-sm);
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath fill='rgba(255,255,255,0.5)' d='M5 6L0 0h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  padding-right: var(--space-8);
  transition: background var(--transition-fast);
}
.class-switcher select:focus {
  background-color: rgba(255,255,255,0.12);
  outline: none;
}
.class-switcher select option {
  background: var(--color-bg-sidebar);
  color: var(--color-white);
}

.sidebar.collapsed .class-switcher { display: none; }

/* 导航区 */
.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-3) var(--space-2);
}

.nav-section {
  margin-bottom: var(--space-4);
}

.nav-section-title {
  font-size: var(--text-xs);
  color: rgba(255,255,255,0.3);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0 var(--space-2) var(--space-2);
  white-space: nowrap;
  overflow: hidden;
  transition: opacity var(--transition-base);
}
.sidebar.collapsed .nav-section-title { opacity: 0; }

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  color: rgba(255,255,255,0.6);
  font-size: var(--text-sm);
  white-space: nowrap;
  margin-bottom: 2px;
  position: relative;
}

.nav-item:hover {
  background: rgba(255,255,255,0.08);
  color: var(--color-white);
}

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

.nav-item.active::before {
  content: '';
  position: absolute;
  left: 0; top: 20%; bottom: 20%;
  width: 3px;
  background: var(--color-primary);
  border-radius: 0 var(--radius-full) var(--radius-full) 0;
}

.nav-icon {
  font-size: 1.1rem;
  width: 20px;
  text-align: center;
  flex-shrink: 0;
}

.nav-label {
  flex: 1;
  transition: opacity var(--transition-base);
}
.sidebar.collapsed .nav-label { opacity: 0; width: 0; overflow: hidden; }

/* Tooltip for collapsed state */
.nav-item[data-tooltip] {
  position: relative;
}
.sidebar.collapsed .nav-item[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  left: calc(100% + var(--space-2));
  top: 50%;
  transform: translateY(-50%);
  background: var(--color-text-primary);
  color: var(--color-white);
  font-size: var(--text-xs);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
  z-index: 999;
}
.sidebar.collapsed .nav-item[data-tooltip]:hover::after {
  opacity: 1;
}

/* 侧边栏底部 */
.sidebar-footer {
  padding: var(--space-4);
  border-top: 1px solid rgba(255,255,255,0.06);
  flex-shrink: 0;
}

.sidebar-user {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition-fast);
}
.sidebar-user:hover { background: rgba(255,255,255,0.06); }
.sidebar-user-info { overflow: hidden; transition: opacity var(--transition-base); }
.sidebar.collapsed .sidebar-user-info { opacity: 0; width: 0; }
.sidebar-user-name { font-size: var(--text-sm); color: var(--color-white); font-weight: var(--font-medium); }
.sidebar-user-role { font-size: var(--text-xs); color: rgba(255,255,255,0.4); }

/* 折叠按钮 */
.sidebar-toggle {
  position: absolute;
  top: var(--space-4);
  right: calc(-14px);
  width: 28px; height: 28px;
  background: var(--color-bg-card);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-bounce);
  z-index: 1;
}
.sidebar-toggle:hover {
  background: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}
.sidebar.collapsed .sidebar-toggle { transform: rotate(180deg); }

/* ── 主内容区 ────────────────────────────────────────── */
.main-content {
  flex: 1;
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: margin-left var(--transition-base);
}
.sidebar.collapsed ~ .main-content {
  margin-left: var(--sidebar-width-collapsed);
}

/* ── 顶部导航栏 ─────────────────────────────────────── */
.top-header {
  height: var(--header-height);
  background: var(--color-bg-card);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6);
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  box-shadow: 0 1px 4px rgba(255,107,107,0.06);
  flex-shrink: 0;
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.page-title {
  font-size: var(--text-xl);
  font-weight: var(--font-semibold);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}
.breadcrumb-item { cursor: pointer; }
.breadcrumb-item:hover { color: var(--color-primary); }
.breadcrumb-sep { opacity: 0.4; }
.breadcrumb-item.current { color: var(--color-text-primary); font-weight: var(--font-medium); cursor: default; }

.header-right {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* 学期选择器 */
.semester-badge {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-primary-bg);
  border: 1px solid var(--color-primary-lighter);
  border-radius: var(--radius-full);
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: var(--font-medium);
  color: var(--color-primary-dark);
}

/* 通知铃铛 */
.notif-btn {
  position: relative;
  width: 36px; height: 36px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}
.notif-btn:hover {
  background: var(--color-primary-bg);
  color: var(--color-primary);
}
.notif-dot {
  position: absolute;
  top: 6px; right: 6px;
  width: 8px; height: 8px;
  background: var(--color-primary);
  border-radius: 50%;
  border: 2px solid var(--color-white);
}

/* ── 内容页面区 ─────────────────────────────────────── */
.page-content {
  flex: 1;
  padding: var(--space-6);
  max-width: var(--content-max-width);
  width: 100%;
}

.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
  gap: var(--space-3);
}
.page-header-left {}
.page-header-title {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-1);
}
.page-header-desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}
.page-header-actions {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

/* 工具栏 */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
  flex-wrap: wrap;
}
.toolbar-left, .toolbar-right {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

/* ── 移动端响应 ─────────────────────────────────────── */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    width: var(--sidebar-width) !important;
  }
  .sidebar.mobile-open {
    transform: translateX(0);
  }
  .main-content {
    margin-left: 0 !important;
  }
  .page-content {
    padding: var(--space-4);
  }
  .top-header {
    padding: 0 var(--space-4);
  }
  .mobile-menu-btn {
    display: flex !important;
  }
}

.mobile-menu-btn {
  display: none;
  width: 36px; height: 36px;
  border-radius: var(--radius-md);
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
}
.mobile-menu-btn:hover { background: var(--color-border); }

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: calc(var(--z-sidebar) - 1);
}
@media (max-width: 768px) {
  .sidebar-overlay.active { display: block; }
}