/* ============================================
   管理后台样式 - 深色科技风格 v2
   ============================================ */

/* === 深色主题变量（默认） === */
.admin-header {
    background: rgba(11, 15, 26, 0.95);
    border-bottom: 1px solid var(--border);
}

.admin-sidebar {
    background: var(--bg-secondary);
    border-right: 1px solid var(--border);
}

.admin-nav-item:hover,
.admin-nav-item.active {
    background: var(--bg-hover);
}

.admin-nav-item.active::before {
    background: var(--grad-brand);
}

/* === 亮色主题（护眼模式） === */
[data-theme="light"] .admin-header {
    background: rgba(250, 249, 247, 0.95);
    border-bottom: 1px solid rgba(0,0,0,0.06);
}

[data-theme="light"] .admin-header::after {
    background: linear-gradient(90deg, transparent 0%, rgba(79,142,247,0.3) 50%, transparent 100%);
}

[data-theme="light"] .admin-sidebar {
    background: #f0ede8;
    border-right: 1px solid rgba(0,0,0,0.06);
}

[data-theme="light"] .admin-nav-item {
    color: var(--text-primary);
}

[data-theme="light"] .admin-nav-item:hover,
[data-theme="light"] .admin-nav-item.active {
    background: rgba(79,142,247,0.1);
}

[data-theme="light"] .admin-nav-item.active {
    color: var(--blue);
}

/* === 暖色主题 === */
[data-theme="warm"] .admin-header {
    background: rgba(252, 248, 240, 0.95);
    border-bottom: 1px solid rgba(139, 115, 85, 0.08);
}

[data-theme="warm"] .admin-header::after {
    background: linear-gradient(90deg, transparent 0%, rgba(232, 160, 64, 0.3) 50%, transparent 100%);
}

[data-theme="warm"] .admin-sidebar {
    background: #f5efe4;
    border-right: 1px solid rgba(139, 115, 85, 0.08);
}

[data-theme="warm"] .admin-nav-item {
    color: var(--text-primary);
}

[data-theme="warm"] .admin-nav-item:hover,
[data-theme="warm"] .admin-nav-item.active {
    background: rgba(232, 160, 64, 0.1);
}

[data-theme="warm"] .admin-nav-item.active {
    color: var(--orange);
}

/* === 主题切换器样式 === */
.admin-theme-switcher {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 4px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    position: relative;
}

.admin-theme-switcher .theme-btn {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    border-radius: 8px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    z-index: 1;
}

.admin-theme-switcher .theme-btn:hover {
    color: var(--text-primary);
    background: var(--bg-hover);
}

.admin-theme-switcher .theme-btn.active {
    color: var(--blue);
}

.admin-theme-switcher[data-active="light"] .theme-btn[onclick*="light"] {
    color: var(--blue);
}

.admin-theme-switcher[data-active="warm"] .theme-btn[onclick*="warm"] {
    color: var(--orange);
}

/* 布局 */
.admin-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 64px;
    backdrop-filter: blur(20px);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    z-index: 1001;
}

.admin-header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, rgba(79, 142, 247, 0.5) 50%, transparent 100%);
}

.admin-header-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.admin-logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.admin-logo i {
    font-size: 1.6rem;
    background: var(--grad-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.admin-logo-text {
    font-size: 1.15rem;
    font-weight: 700;
    background: linear-gradient(135deg, #f0f4ff 0%, #8b9dc3 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.admin-badge {
    background: var(--grad-brand);
    color: #fff;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.5px;
}

.admin-header-right {
    display: flex;
    align-items: center;
    gap: 20px;
}

.admin-time {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.admin-user {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
}

.admin-user:hover {
    background: var(--bg-hover);
    border-color: var(--border-bright);
}

.admin-user i:first-child {
    font-size: 1.2rem;
    color: var(--blue);
}

.admin-user i:last-child {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* 侧边栏 */
.admin-sidebar {
    position: fixed;
    top: 64px;
    left: 0;
    bottom: 0;
    width: 240px;
    background: rgba(11, 15, 26, 0.9);
    backdrop-filter: blur(20px);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    padding: 20px 0;
    z-index: 1000;
    transition: transform 0.3s ease;
}

.admin-nav {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 0 12px;
}

.admin-nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 16px;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius);
    transition: var(--transition);
    font-weight: 500;
    cursor: pointer;
    background: transparent;
    border: none;
    width: 100%;
    text-align: left;
    font-size: 0.95rem;
}

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

.admin-nav-item.active {
    background: var(--grad-brand);
    color: #fff;
    box-shadow: var(--glow-blue);
}

.admin-nav-item i {
    width: 20px;
    text-align: center;
}

.admin-sidebar-footer {
    padding: 12px;
    border-top: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    gap: 4px;
}

/* 主内容区 */
.admin-main {
    margin-left: 240px;
    margin-top: 64px;
    padding: 24px;
    min-height: calc(100vh - 64px);
}

/* 工具栏按钮 */
.menu-toggle {
    display: none;
    background: var(--bg-card);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 8px 12px;
    border-radius: var(--radius);
    cursor: pointer;
}

/* 章节样式 */
.admin-section {
    display: none;
    animation: fadeIn 0.3s ease;
}

.admin-section.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.admin-section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
    flex-wrap: wrap;
    gap: 16px;
}

.admin-section-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 12px;
}

.admin-section-header h2 i {
    background: var(--grad-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* 统计卡片 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.stat-card {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 24px;
    position: relative;
    overflow: hidden;
}

.stat-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.stat-icon.blue { background: rgba(79, 142, 247, 0.15); color: var(--blue); }
.stat-icon.purple { background: rgba(167, 139, 250, 0.15); color: var(--purple); }
.stat-icon.green { background: rgba(52, 211, 153, 0.15); color: var(--green); }
.stat-icon.orange { background: rgba(251, 191, 36, 0.15); color: var(--orange); }

.stat-info {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
    background: linear-gradient(135deg, #f0f4ff 0%, #8b9dc3 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.stat-glow {
    position: absolute;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    filter: blur(40px);
    opacity: 0.3;
    right: -20px;
    bottom: -20px;
}

.stat-glow.blue { background: var(--blue); }
.stat-glow.purple { background: var(--purple); }
.stat-glow.green { background: var(--green); }
.stat-glow.orange { background: var(--orange); }

/* 仪表盘网格 */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 20px;
}

/* 卡片通用样式 */
.glass-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
}

.card-header {
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
}

.card-header h3 {
    font-size: 1rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
}

.card-body {
    padding: 16px 20px;
}

/* 视频工具栏 */
.video-toolbar {
    padding: 16px 20px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.toolbar-left {
    display: flex;
    align-items: center;
    gap: 16px;
}

.toolbar-center {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
}

.toolbar-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.selected-count {
    color: var(--text-secondary);
    font-size: 0.85rem;
    padding: 4px 12px;
    background: var(--bg-secondary);
    border-radius: 20px;
}

/* 复选框样式 */
.checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--blue);
    cursor: pointer;
}

.select-all input {
    width: 20px;
    height: 20px;
}

/* 筛选器 */
.filter-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.filter-group label {
    color: var(--text-secondary);
    font-size: 0.85rem;
    white-space: nowrap;
}

.filter-group label i {
    color: var(--blue);
}

.filter-group select,
.filter-group input {
    padding: 8px 12px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-primary);
    font-size: 0.85rem;
    min-width: 120px;
}

.filter-group input {
    min-width: 180px;
}

.filter-group select:focus,
.filter-group input:focus {
    outline: none;
    border-color: var(--blue);
}

/* 视频列表 */
.video-list {
    padding: 0;
    overflow: hidden;
}

.video-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}

.video-item:hover {
    background: var(--bg-hover);
}

.video-item:last-child {
    border-bottom: none;
}

.video-item input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--blue);
    flex-shrink: 0;
}

.video-thumb {
    width: 80px;
    height: 50px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 1.5rem;
    flex-shrink: 0;
}

.video-info {
    flex: 1;
    min-width: 0;
}

.video-title {
    font-weight: 500;
    margin-bottom: 4px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.video-meta {
    font-size: 0.8rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 12px;
}

.video-actions {
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

.video-status {
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.video-status.ok {
    background: rgba(52, 211, 153, 0.15);
    color: var(--green);
}

.video-status.missing {
    background: rgba(248, 113, 113, 0.15);
    color: var(--red);
}

/* 分类网格 */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}

.category-card {
    padding: 20px;
    transition: var(--transition);
}

.category-card:hover {
    transform: translateY(-2px);
    border-color: var(--border-bright);
}

.category-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: 12px;
}

.category-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius);
    background: var(--bg-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.category-actions {
    display: flex;
    gap: 8px;
}

.category-name {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.category-desc {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 12px;
}

.category-stats {
    display: flex;
    gap: 20px;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.category-stats span {
    display: flex;
    align-items: center;
    gap: 6px;
}

/* 数据表格 */
.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th,
.data-table td {
    padding: 14px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.data-table th {
    background: var(--bg-secondary);
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.data-table th i,
.data-table td i {
    margin-right: 6px;
    color: var(--text-muted);
}

.data-table tr:hover td {
    background: var(--bg-hover);
}

.data-table td {
    font-size: 0.9rem;
}

/* 设置网格 */
.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 20px;
}

/* 表单样式 */
.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 14px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--blue);
    box-shadow: 0 0 0 3px rgba(79, 142, 247, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

.form-hint {
    display: block;
    margin-top: 6px;
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* 上传区域 */
.upload-area {
    border: 2px dashed var(--border);
    border-radius: var(--radius-lg);
    padding: 40px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    margin-bottom: 20px;
}

.upload-area:hover {
    border-color: var(--blue);
    background: rgba(79, 142, 247, 0.05);
}

.upload-area i {
    font-size: 3rem;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.upload-area p {
    font-size: 1rem;
    margin-bottom: 8px;
}

.upload-area span {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* 上传提示文字 */
.upload-hint {
    font-size: 0.85rem !important;
    color: var(--blue) !important;
}

/* 上传标签页 */
.upload-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
}

.upload-tab {
    flex: 1;
    padding: 12px 16px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.upload-tab:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.upload-tab.active {
    background: var(--grad-brand);
    color: #fff;
    border-color: transparent;
}

/* 上传标签内容 */
.upload-tab-content {
    display: none;
}

.upload-tab-content.active {
    display: block;
}

/* 批量上传区域 */
.upload-folder-btn {
    text-align: center;
    margin-bottom: 16px;
}

/* 文件上传队列 */
.upload-queue {
    max-height: 250px;
    overflow-y: auto;
    margin-bottom: 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--bg-secondary);
}

.queue-item {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    border-bottom: 1px solid var(--border);
    gap: 12px;
}

.queue-item:last-child {
    border-bottom: none;
}

.queue-item-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(79, 142, 247, 0.1);
    border-radius: var(--radius);
    color: var(--blue);
}

.queue-item-info {
    flex: 1;
    min-width: 0;
}

.queue-item-name {
    font-size: 0.9rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.queue-item-size {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.queue-item-status {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.queue-item-status.pending {
    color: var(--text-muted);
}

.queue-item-status.uploading {
    color: var(--blue);
}

.queue-item-status.success {
    color: var(--green);
}

.queue-item-status.error {
    color: var(--red);
}

.queue-item-remove {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    border-radius: var(--radius);
    transition: var(--transition);
}

.queue-item-remove:hover {
    background: rgba(255, 77, 77, 0.1);
    color: var(--red);
}

/* 批量上传选项 */
.upload-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.upload-options .form-group:first-child {
    grid-column: 1 / -1;
}

/* 批量上传总进度 */
.batch-progress {
    margin-top: 16px;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
}

.batch-progress-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
    font-size: 0.9rem;
}

/* 上传进度 */
.upload-progress {
    margin-bottom: 20px;
}

.progress-bar {
    height: 8px;
    background: var(--bg-secondary);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 8px;
}

.progress-fill {
    height: 100%;
    background: var(--grad-brand);
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* 扫描选项 */
.scan-options {
    display: flex;
    gap: 20px;
    margin: 16px 0;
}

.scan-result {
    margin-top: 16px;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    max-height: 300px;
    overflow-y: auto;
}

.scan-item {
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
}

.scan-item:last-child {
    border-bottom: none;
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 18px;
    border: none;
    border-radius: var(--radius);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    background: var(--grad-brand);
    color: #fff;
}

.btn-primary:hover {
    box-shadow: var(--glow-blue);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--bg-card-2);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--bg-hover);
    border-color: var(--border-bright);
}

.btn-danger {
    background: rgba(248, 113, 113, 0.15);
    color: var(--red);
    border: 1px solid rgba(248, 113, 113, 0.3);
}

.btn-danger:hover:not(:disabled) {
    background: rgba(248, 113, 113, 0.25);
}

.btn-danger:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.8rem;
}

.section-actions {
    display: flex;
    gap: 12px;
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.modal-header h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1rem;
}

.modal-close {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 4px;
    transition: var(--transition);
}

.modal-close:hover {
    color: var(--text-primary);
}

.modal-body {
    padding: 24px;
}

.modal-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: flex-end;
    gap: 12px;
}

/* Toast 提示 */
.toast-container {
    position: fixed;
    top: 80px;
    right: 24px;
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    padding: 14px 20px;
    border-radius: var(--radius);
    background: var(--bg-card);
    border: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 12px;
    box-shadow: var(--shadow-lg);
    animation: slideIn 0.3s ease;
    min-width: 280px;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(100px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.toast.success {
    border-color: rgba(52, 211, 153, 0.5);
}

.toast.success i {
    color: var(--green);
}

.toast.error {
    border-color: rgba(248, 113, 113, 0.5);
}

.toast.error i {
    color: var(--red);
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 40px;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 2.5rem;
    margin-bottom: 12px;
    opacity: 0.5;
}

/* 课程统计 */
.course-stat-item {
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
}

.course-stat-item:last-child {
    border-bottom: none;
}

.course-stat-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
}

.course-stat-name {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
}

.course-stat-count {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.course-stat-bar {
    height: 8px;
    background: var(--bg-secondary);
    border-radius: 4px;
    overflow: hidden;
}

.course-stat-fill {
    height: 100%;
    border-radius: 4px;
    transition: width 0.5s ease;
}

/* 最近上传 */
.recent-upload-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 0;
    border-bottom: 1px solid var(--border);
}

.recent-upload-item:last-child {
    border-bottom: none;
}

.recent-upload-icon {
    width: 36px;
    height: 36px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    flex-shrink: 0;
}

.recent-upload-info {
    flex: 1;
    min-width: 0;
}

.recent-upload-name {
    display: block;
    font-size: 0.9rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-bottom: 2px;
}

.recent-upload-course {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.recent-upload-status {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    flex-shrink: 0;
}

.recent-upload-status.ok {
    color: var(--green);
}

.recent-upload-status.error {
    color: var(--red);
}

/* 加载状态 */
.loading {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
}

.loading i {
    margin-right: 8px;
}

/* 响应式 */
@media (max-width: 1024px) {
    .admin-sidebar {
        transform: translateX(-100%);
    }
    
    .admin-sidebar.open {
        transform: translateX(0);
    }
    
    .admin-main {
        margin-left: 0;
    }
    
    .menu-toggle {
        display: block;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .settings-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .admin-header {
        padding: 0 16px;
    }
    
    .admin-main {
        padding: 16px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .video-toolbar {
        flex-direction: column;
        align-items: stretch;
    }
    
    .toolbar-left,
    .toolbar-center,
    .toolbar-right {
        justify-content: space-between;
    }
    
    .section-actions {
        flex-direction: column;
    }
    
    .data-table {
        font-size: 0.8rem;
    }
    
    .data-table th,
    .data-table td {
        padding: 10px 8px;
    }
}

/* ============================================
   视频管理标签页
   ============================================ */
.admin-tabs {
    display: flex;
    gap: 8px;
    padding: 12px 16px;
    margin-bottom: 16px;
}

.admin-tab {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 500;
}

.admin-tab:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.admin-tab.active {
    background: var(--grad-brand);
    color: #fff;
    border-color: transparent;
}

.tab-badge {
    background: rgba(255, 255, 255, 0.2);
    color: #fff;
    padding: 2px 8px;
    border-radius: 10px;
    font-size: 0.75rem;
    font-weight: 600;
}

.tab-badge.orange {
    background: var(--orange);
}

/* 未分类视频列表项 */
.uncat-item {
    display: flex;
    align-items: center;
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
    gap: 12px;
    transition: var(--transition);
}

.uncat-item:hover {
    background: var(--bg-hover);
}

.uncat-item:last-child {
    border-bottom: none;
}

.uncat-item input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--blue);
    cursor: pointer;
}

.uncat-thumb {
    width: 48px;
    height: 48px;
    background: rgba(79, 142, 247, 0.1);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--blue);
    flex-shrink: 0;
}

.uncat-info {
    flex: 1;
    min-width: 0;
}

.uncat-name {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-bottom: 4px;
}

.uncat-meta {
    font-size: 0.8rem;
    color: var(--text-muted);
    display: flex;
    gap: 16px;
}

.uncat-meta span {
    display: flex;
    align-items: center;
    gap: 4px;
}

.uncat-status {
    font-size: 0.8rem;
    padding: 4px 10px;
    border-radius: 12px;
    background: rgba(248, 113, 113, 0.15);
    color: var(--red);
}

.uncat-status.registed {
    background: rgba(52, 211, 153, 0.15);
    color: var(--green);
}

/* 同步进度 */
.sync-progress {
    margin-top: 16px;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    display: none;
}

.sync-progress.active {
    display: block;
}

.sync-progress-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.sync-progress-text {
    font-size: 0.9rem;
    color: var(--text-primary);
}

.sync-progress-count {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* 未分类为空状态 */
.uncat-empty {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}

.uncat-empty i {
    font-size: 4rem;
    margin-bottom: 16px;
    opacity: 0.3;
    color: var(--green);
}

.uncat-empty h3 {
    font-size: 1.1rem;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.uncat-empty p {
    font-size: 0.9rem;
}