:root {
    --primary-color: #1a73e8;
    --secondary-color: #1a73e8;
    --bg-color: #f9f9f9;
    --card-bg: #ffffff;
    --text-primary: #202124;
    --text-secondary: #5f6368;
    --hover-bg: #f1f3f4;
    --border-color: #e0e0e0;
    --success-color: #1e8e3e;
    --danger-color: #d93025;
    --sidebar-width: 240px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
}

.navbar {
    background-color: var(--card-bg);
    height: 56px;
    display: flex;
    align-items: center;
    padding: 0 16px;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: 100%;
}

.nav-left, .nav-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

.nav-center {
    flex: 1;
    max-width: 600px;
    margin: 0 40px;
}

.menu-icon {
    font-size: 24px;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: background-color 0.2s;
}

.menu-icon:hover {
    background-color: var(--hover-bg);
}

.logo {
    color: var(--text-primary);
    text-decoration: none;
    font-size: 20px;
    font-weight: bold;
    display: flex;
    align-items: center;
    gap: 8px;
}

.search-box {
    display: flex;
    align-items: center;
    border: 1px solid var(--border-color);
    border-radius: 40px;
    overflow: hidden;
    background-color: #fff;
}

.search-box input {
    flex: 1;
    border: none;
    outline: none;
    padding: 10px 16px;
    background-color: transparent;
    color: var(--text-primary);
    font-size: 14px;
}

.search-btn {
    border: none;
    background-color: var(--hover-bg);
    color: var(--text-primary);
    padding: 10px 20px;
    cursor: pointer;
    font-size: 16px;
    border-left: 1px solid var(--border-color);
}

.search-btn:hover {
    background-color: var(--border-color);
}

.admin-link {
    color: var(--text-primary);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 4px;
    background-color: var(--primary-color);
    color: white;
    transition: background-color 0.2s;
    font-weight: 500;
}

.admin-link:hover {
    background-color: #1557b0;
}

/* 顶部分类栏 */
.category-bar {
    position: fixed;
    top: 56px;
    left: 0;
    right: 0;
    z-index: 999;
    background: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    padding: 8px 0;
    min-height: 44px;
}

.category-scroll {
    display: flex;
    align-items: center;
    gap: 8px;
    overflow-x: auto;
    padding: 0 16px;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}

.category-scroll::-webkit-scrollbar {
    display: none;
}

.category-chip {
    flex-shrink: 0;
    padding: 8px 16px;
    border: 1px solid var(--border-color);
    border-radius: 20px;
    background: var(--card-bg);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
    white-space: nowrap;
    transition: all 0.2s;
}

.category-chip:hover {
    background: var(--hover-bg);
}

.category-chip.active {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
}

/* 排序栏 */
.sort-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    padding: 0 4px;
}

.sort-label {
    font-size: 14px;
    color: var(--text-secondary);
}

.sort-select {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--card-bg);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
}

.main-container {
    display: flex;
    margin-top: 56px;
    padding-top: 52px;
    min-height: calc(100vh - 56px);
}

.sidebar-overlay {
    display: none;
}

@media (min-width: 1025px) {
    .sidebar-overlay {
        display: none !important;
    }
}

@media (max-width: 768px) {
    .main-container {
        padding-top: 52px;
    }
}

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--card-bg);
    padding: 12px 0;
    position: fixed;
    left: 0;
    top: 56px;
    bottom: 0;
    overflow-y: auto;
    border-right: 1px solid var(--border-color);
}

.sidebar-section {
    padding: 8px 12px;
}

.sidebar-section h3 {
    padding: 8px 12px;
    font-size: 14px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.categories-list {
    list-style: none;
}

.categories-list li {
    margin: 2px 0;
}

.categories-list a {
    display: block;
    padding: 10px 12px;
    color: var(--text-primary);
    text-decoration: none;
    border-radius: 8px;
    transition: background-color 0.2s;
}

.categories-list a:hover {
    background-color: var(--hover-bg);
}

.categories-list a.active {
    background-color: var(--hover-bg);
    font-weight: 600;
}

.content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 24px;
}

.video-section {
    margin-bottom: 40px;
}

.section-header {
    margin-bottom: 16px;
}

.section-header h2 {
    font-size: 20px;
    font-weight: 600;
}

.section-header p {
    color: var(--text-secondary);
    margin-top: 4px;
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
}

.video-card {
    cursor: pointer;
    transition: transform 0.2s;
    border-radius: 12px;
    overflow: hidden;
    background-color: var(--card-bg);
}

.video-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.video-thumbnail {
    width: 100%;
    aspect-ratio: 16/9;
    background-color: #f0f0f0;
    border-radius: 12px;
    overflow: hidden;
    position: relative;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.video-info {
    padding: 12px 0;
}

.video-title {
    font-size: 14px;
    font-weight: 500;
    line-height: 1.4;
    color: var(--text-primary);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    margin-bottom: 8px;
}

.video-meta {
    font-size: 12px;
    color: var(--text-secondary);
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.video-tags {
    margin-top: 8px;
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.tag {
    font-size: 11px;
    padding: 3px 8px;
    background-color: var(--hover-bg);
    color: var(--text-secondary);
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

.category-badge {
    font-size: 11px;
    padding: 3px 8px;
    background-color: #e8f0fe;
    color: var(--primary-color);
    border-radius: 4px;
    text-decoration: none;
    display: inline-block;
    font-weight: 500;
}

.no-videos {
    color: var(--text-secondary);
    padding: 40px;
    text-align: center;
}

.video-player-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 24px;
}

.video-player {
    width: 100%;
    background-color: #000;
    border-radius: 12px;
    overflow: hidden;
    margin-bottom: 16px;
}

.video-player video {
    width: 100%;
    display: block;
}

.video-details {
    margin-bottom: 24px;
}

.video-details h1 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.video-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.video-description {
    background-color: var(--hover-bg);
    padding: 16px;
    border-radius: 12px;
    margin-top: 12px;
    border: 1px solid var(--border-color);
}

.related-videos {
    margin-top: 32px;
}

.related-videos h3 {
    font-size: 18px;
    margin-bottom: 16px;
}

.admin-navbar {
    background-color: var(--primary-color);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.admin-navbar .logo,
.admin-navbar .btn-secondary {
    color: white;
}

.admin-navbar .btn-secondary {
    background-color: rgba(255,255,255,0.2);
}

.admin-navbar .btn-secondary:hover {
    background-color: rgba(255,255,255,0.3);
}

.admin-container {
    display: flex;
    margin-top: 56px;
    min-height: calc(100vh - 56px);
}

.admin-sidebar {
    width: 240px;
    background-color: var(--card-bg);
    padding: 20px 0;
    position: fixed;
    left: 0;
    top: 56px;
    bottom: 0;
    border-right: 1px solid var(--border-color);
}

.admin-menu {
    list-style: none;
}

.admin-menu li {
    margin: 4px 0;
}

.admin-menu a {
    display: block;
    padding: 12px 24px;
    color: var(--text-primary);
    text-decoration: none;
    transition: background-color 0.2s;
}

.admin-menu a:hover {
    background-color: var(--hover-bg);
}

.admin-menu a.active {
    background-color: #e8f0fe;
    border-left: 3px solid var(--primary-color);
    font-weight: 600;
    color: var(--primary-color);
}

.admin-content {
    flex: 1;
    margin-left: 240px;
    padding: 32px;
}

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

.content-header h1 {
    font-size: 28px;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.stat-card {
    background-color: var(--card-bg);
    padding: 24px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 16px;
    border: 1px solid var(--border-color);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.stat-icon {
    font-size: 48px;
}

.stat-info h3 {
    font-size: 32px;
    font-weight: 600;
    margin-bottom: 4px;
}

.stat-info p {
    color: var(--text-secondary);
    font-size: 14px;
}

.dashboard-section {
    margin-bottom: 40px;
}

.dashboard-section h2 {
    font-size: 22px;
    margin-bottom: 16px;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.category-card {
    background-color: var(--card-bg);
    padding: 20px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    transition: box-shadow 0.2s;
}

.category-card:hover {
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.category-card h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.category-card p {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 16px;
    min-height: 40px;
}

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

.table-container {
    background-color: var(--card-bg);
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.admin-table {
    width: 100%;
    border-collapse: collapse;
}

.admin-table thead {
    background-color: var(--hover-bg);
}

.admin-table th {
    padding: 16px;
    text-align: left;
    font-weight: 600;
    font-size: 14px;
}

.admin-table td {
    padding: 16px;
    border-top: 1px solid var(--border-color);
    font-size: 14px;
}

.admin-table tbody tr:hover {
    background-color: var(--hover-bg);
}

.badge-success {
    padding: 4px 12px;
    background-color: #0f9d58;
    color: white;
    border-radius: 4px;
    font-size: 12px;
}

.badge-danger {
    padding: 4px 12px;
    background-color: var(--danger-color);
    color: white;
    border-radius: 4px;
    font-size: 12px;
}

.upload-container {
    max-width: 800px;
    background-color: var(--card-bg);
    padding: 32px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    font-size: 14px;
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"],
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--card-bg);
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input[type="text"]:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.1);
}

.form-group textarea {
    resize: vertical;
}

.file-upload {
    position: relative;
}

.file-upload input[type="file"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.file-upload-label {
    display: block;
    padding: 12px;
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.2s;
}

.file-upload-label:hover {
    border-color: var(--secondary-color);
}

.file-upload-label span {
    color: var(--text-secondary);
}

.thumbnail-preview {
    margin-top: 12px;
}

.thumbnail-preview img {
    max-width: 300px;
    border-radius: 8px;
}

.upload-progress {
    margin: 24px 0;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background-color: var(--hover-bg);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 8px;
}

.progress-fill {
    height: 100%;
    background-color: var(--primary-color);
    transition: width 0.3s;
}

#progressText {
    color: var(--text-secondary);
    font-size: 14px;
}

.form-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 24px;
}

.btn-primary,
.btn-secondary,
.btn-danger,
.btn-small {
    padding: 10px 20px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: #1557b0;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

.btn-primary:disabled {
    background-color: var(--hover-bg);
    cursor: not-allowed;
}

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

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

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

.btn-danger:hover {
    background-color: #cc0000;
}

.btn-small {
    padding: 6px 12px;
    font-size: 12px;
}

.modal {
    display: none;
    position: fixed;
    z-index: 2000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: var(--card-bg);
    border-radius: 12px;
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 8px 32px rgba(0,0,0,0.2);
}

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

.modal-header h2 {
    font-size: 20px;
}

.close {
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    color: var(--text-secondary);
}

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

.modal form {
    padding: 24px;
}

@media (max-width: 1024px) {
    .sidebar {
        position: fixed;
        left: -280px;
        top: 108px;
        width: 260px;
        height: calc(100vh - 108px);
        background: var(--card-bg);
        z-index: 998;
        transition: left 0.3s ease;
        box-shadow: 4px 0 12px rgba(0,0,0,0.15);
        overflow-y: auto;
    }
    
    .sidebar.sidebar-open {
        left: 0;
    }
    
    .sidebar-overlay {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(0,0,0,0.4);
        z-index: 997;
        opacity: 0;
        visibility: hidden;
        pointer-events: none;
        transition: opacity 0.3s, visibility 0.3s;
    }
    
    .sidebar-overlay.show {
        opacity: 1;
        visibility: visible;
        pointer-events: auto;
    }
    
    .admin-sidebar {
        width: 0;
        padding: 0;
        border: none;
    }
    
    .content {
        margin-left: 0;
    }
    
    .admin-content {
        margin-left: 0;
    }
    
    .video-grid {
        grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    }
}

@media (max-width: 768px) {
    .nav-center.nav-search {
        display: none;
    }
    
    .category-bar {
        padding: 6px 0;
        min-height: 40px;
    }
    
    .category-chip {
        padding: 6px 12px;
        font-size: 13px;
    }
    
    .sort-bar {
        padding: 0 12px;
        margin-bottom: 12px;
    }
    
    .video-grid {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
        gap: 12px;
        padding: 0 12px;
    }
    
    .video-section {
        padding: 0;
    }
    
    .content {
        padding: 12px 0;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .categories-grid {
        grid-template-columns: 1fr;
    }
}