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

        :root {
            --bg-primary: #ffffff;
            --bg-secondary: #f8f9fa;
            --bg-dark: #0f0f0f;
            --bg-darker: #000000;
            --text-primary: #1a1a1a;
            --text-secondary: #6c757d;
            --text-white: #ffffff;
            --accent-red: #ff0000;
            --accent-blue: #0066ff;
            --border-light: #e9ecef;
            --shadow-light: 0 2px 8px rgba(0, 0, 0, 0.1);
            --shadow-medium: 0 4px 24px rgba(0, 0, 0, 0.15);
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;
        }

        html, body {
            height: 100%;
            /*overflow: hidden;*/
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
            background: var(--bg-primary);
            color: var(--text-primary);
            line-height: 1.6;
        }

        /* 主容器 - 移除顶部导航栏的行 */
        .app-container {
            display: grid;
            grid-template-columns: 1fr 380px;
            grid-template-rows: 1fr; /* 原本是 60px 1fr，现在只有 1fr */
            height: 100vh;
            width: 100vw;
            /*position: fixed;*/
            top: 0;
            left: 0;
            transition: grid-template-columns 0.3s ease;
            margin-top:80px;
        }

        .app-container.sidebar-collapsed {
            grid-template-columns: 1fr 0px;
        }

        .app-container.mobile-layout {
            grid-template-columns: 1fr;
            grid-template-rows: 1fr 0px; /* 原本是 60px 1fr 0px，现在简化为 1fr 0px */
        }

        .app-container.mobile-layout.sidebar-open {
            grid-template-rows: 1fr 300px; /* 原本是 60px 1fr 300px，现在简化为 1fr 300px */
        }

        /* 顶部导航栏 - 改为浮动在视频区域上方 */
        .top-nav {
            position: absolute;
            top: 1.5rem;
            right: 1.5rem;
            background: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(10px);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-md);
            padding: 0.5rem 1rem;
            z-index: 1000; /* 提高层级确保在视频控制栏上方 */
            display: flex;
            align-items: center;
            justify-content: flex-end;
            /*
            gap: 1rem;
            box-shadow: var(--shadow-light);
            width: auto;
            min-width: 150px;
            */
        }

        .nav-brand {
            display: flex;
            align-items: center;
            gap: 1rem;
        }

        .logo {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--text-primary);
            text-decoration: none;
            /*display: none; /* 隐藏logo以节省空间 */
        }

        .sidebar-toggle {
            width: 40px;
            height: 40px;
            background: transparent;
            border: none;
            border-radius: var(--radius-sm);
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.2s ease;
            color: var(--text-secondary);
        }

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

        .nav-actions {
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        /* 主内容区域 */
        .main-content {
            grid-column: 1;
            display: flex;
            flex-direction: column;
            background: var(--bg-primary);
            position: relative;
            overflow: hidden;
            grid-row: 1; /* 明确指定从第一行开始 */
        }

        /* 视频播放器区域 */
        .video-player-section {
            flex: 1;
            display: flex;
            align-items: center;
            justify-content: center;
            background: var(--bg-darker);
            position: relative;
            overflow: hidden;
        }

        .video-container {
            width: 100%;
            height: 100%;
            max-width: none;
            max-height: none;
            position: relative;
            background: var(--bg-darker);
        }

        .main-video {
            width: 100%;
            height: 100%;
            object-fit: contain;
            background: var(--bg-darker);
        }

        /* 现代化控制栏 - YouTube风格 */
        .video-controls {
            position: absolute;
            bottom: 0;
            left: 0;
            right: 0;
            background: linear-gradient(transparent, rgba(0, 0, 0, 0.8));
            padding: 1.5rem 1rem 1rem;
            opacity: 0;
            transform: translateY(10px);
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            pointer-events: none;
        }

        .video-container:hover .video-controls {
            opacity: 1;
            transform: translateY(0);
            pointer-events: all;
        }

        .controls-row {
            display: flex;
            align-items: center;
            gap: 1rem;
            margin-bottom: 0.75rem;
        }

        .play-button {
            width: 44px;
            height: 44px;
            background: var(--accent-red);
            border: none;
            border-radius: 50%;
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            justify-content: center;
            transition: all 0.2s ease;
            font-size: 1.1rem;
            flex-shrink: 0;
        }

        .play-button:hover {
            background: #e60000;
            transform: scale(1.05);
        }

        .progress-container {
            flex: 1;
            height: 5px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 2.5px;
            cursor: pointer;
            position: relative;
            overflow: hidden;
        }

        .progress-bar {
            height: 100%;
            background: var(--accent-red);
            border-radius: 2.5px;
            width: 0%;
            transition: width 0.1s ease;
        }

        .progress-handle {
            position: absolute;
            top: 50%;
            left: 0%;
            transform: translate(-50%, -50%);
            width: 14px;
            height: 14px;
            background: var(--accent-red);
            border-radius: 50%;
            opacity: 0;
            transition: opacity 0.2s ease;
        }

        .progress-container:hover .progress-handle {
            opacity: 1;
        }

        .time-display {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.85rem;
            color: white;
            min-width: 70px;
            text-align: center;
            flex-shrink: 0;
        }

        .volume-control {
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        .volume-button {
            background: transparent;
            border: none;
            color: white;
            cursor: pointer;
            padding: 0.5rem;
            border-radius: 4px;
            transition: all 0.2s ease;
            font-size: 1.1rem;
        }

        .volume-button:hover {
            background: rgba(255, 255, 255, 0.1);
        }

        .volume-slider {
            width: 80px;
            height: 4px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 2px;
            cursor: pointer;
            position: relative;
        }

        .volume-level {
            height: 100%;
            background: var(--accent-red);
            border-radius: 2px;
            width: 70%;
            transition: width 0.2s ease;
        }

        .control-button {
            background: transparent;
            border: none;
            color: white;
            cursor: pointer;
            padding: 0.5rem;
            border-radius: 4px;
            transition: all 0.2s ease;
            font-size: 1rem;
            flex-shrink: 0;
        }

        .control-button:hover {
            background: rgba(255, 255, 255, 0.1);
        }

        /* 视频信息区域 */
        .video-info {
            padding: 1.5rem;
            background: var(--bg-primary);
            border-top: 1px solid var(--border-light);
            overflow-y: auto;
        }

        .video-meta {
            max-width: 1200px;
            margin: 0 auto;
        }

        .video-title {
            font-size: 1.5rem;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 0.5rem;
            line-height: 1.3;
        }

        .video-stats {
            display: flex;
            align-items: center;
            gap: 1rem;
            margin-bottom: 1rem;
            color: var(--text-secondary);
            font-size: 0.9rem;
            flex-wrap: wrap;
        }

        .video-description {
            color: var(--text-secondary);
            font-size: 0.95rem;
            line-height: 1.6;
            max-width: 800px;
        }

        /* 侧边栏 - 现代设计 */
        .video-sidebar {
            grid-column: 2;
            background: var(--bg-secondary);
            border-left: 1px solid var(--border-light);
            display: flex;
            flex-direction: column;
            overflow: hidden;
            position: relative;
            grid-row: 1; /* 明确指定从第一行开始 */
        }

        .sidebar-header {
            padding: 1.5rem;
            background: var(--bg-primary);
            border-bottom: 1px solid var(--border-light);
            position: sticky;
            top: 0;
            z-index: 10;
        }

        .sidebar-title {
            font-size: 1.25rem;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: 1rem;
        }

        .search-input {
            width: 100%;
            padding: 0.75rem 1rem;
            background: var(--bg-secondary);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-sm);
            color: var(--text-primary);
            font-size: 0.9rem;
            transition: all 0.2s ease;
        }

        .search-input:focus {
            outline: none;
            border-color: var(--accent-blue);
            box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
        }

        .search-input::placeholder {
            color: var(--text-secondary);
        }

        /* 视频列表 */
        .video-list {
            flex: 1;
            overflow-y: auto;
            padding: 1rem;
        }

        .video-list::-webkit-scrollbar {
            width: 6px;
        }

        .video-list::-webkit-scrollbar-track {
            background: var(--bg-secondary);
        }

        .video-list::-webkit-scrollbar-thumb {
            background: var(--border-light);
            border-radius: 3px;
        }

        .video-item {
            display: flex;
            gap: 1rem;
            padding: 0.75rem;
            border-radius: var(--radius-sm);
            cursor: pointer;
            transition: all 0.2s ease;
            margin-bottom: 0.5rem;
            background: var(--bg-primary);
            border: 1px solid var(--border-light);
        }

        .video-item:hover {
            transform: translateY(-1px);
            box-shadow: var(--shadow-light);
            border-color: var(--accent-blue);
        }

        .video-item.active {
            border-color: var(--accent-blue);
            background: rgba(0, 102, 255, 0.05);
        }

        .video-thumbnail {
            width: 120px;
            height: 68px;
            background: var(--bg-dark);
            border-radius: var(--radius-sm);
            overflow: hidden;
            flex-shrink: 0;
            position: relative;
        }

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

        .video-duration {
            position: absolute;
            bottom: 4px;
            right: 4px;
            background: rgba(0, 0, 0, 0.8);
            color: white;
            font-size: 0.7rem;
            padding: 2px 6px;
            border-radius: 4px;
            font-family: 'JetBrains Mono', monospace;
        }

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

        .video-item-title {
            font-size: 0.9rem;
            font-weight: 500;
            color: var(--text-primary);
            margin-bottom: 0.25rem;
            display: -webkit-box;
            -webkit-line-clamp: 2;
            -webkit-box-orient: vertical;
            overflow: hidden;
            line-height: 1.3;
        }

        .video-item-meta {
            font-size: 0.8rem;
            color: var(--text-secondary);
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }

        /* 移动端适配 */
        @media (max-width: 768px) {
            .app-container {
                grid-template-columns: 1fr;
                grid-template-rows: 1fr 0px; /* 移除 60px 的顶部行 */
            }

            .app-container.sidebar-collapsed {
                grid-template-columns: 1fr;
                grid-template-rows: 1fr 0px;
            }

            .app-container.sidebar-open {
                grid-template-rows: 1fr 280px; /* 移除 60px 的顶部行 */
            }

            /* 移动端导航栏 - 缩小尺寸 */
           .top-nav {
                position: absolute;
                top: 2rem;
                right: 2rem;
                background: linear-gradient(135deg, rgba(255, 255, 255, 0.95) 0%, rgba(248, 249, 250, 0.95) 100%);
                backdrop-filter: blur(10px);
                border-radius: 18px;
                padding: 1rem 1.5rem;
                z-index: 1000;
                display: flex;
                align-items: center;
                gap: 1rem;
                box-shadow: 0 6px 24px rgba(0, 0, 0, 0.1);
                border: 1px solid rgba(0, 0, 0, 0.05);
            }
            
            .sidebar-toggle {
                width: 42px;
                height: 42px;
                background: var(--accent-red);
                border: none;
                border-radius: 50%;
                cursor: pointer;
                display: flex;
                align-items: center;
                justify-content: center;
                transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
                color: white;
                box-shadow: 0 4px 12px rgba(255, 0, 0, 0.3);
            }
            
            .sidebar-toggle:hover {
                transform: scale(1.1) rotate(90deg);
                box-shadow: 0 6px 16px rgba(255, 0, 0, 0.4);
            }

            .logo {
                display: none;
            }

            .video-sidebar {
                grid-column: 1;
                grid-row: 2; /* 移动端侧边栏在第二行 */
                border-left: none;
                border-top: 1px solid var(--border-light);
                transform: none;
                transition: none;
            }

            .video-sidebar.hidden {
                display: none;
            }

            .video-title {
                font-size: 1.25rem;
            }

            .video-info {
                padding: 1rem;
            }

            .modern-controls {
                padding: 1rem 0.75rem 0.75rem;
            }

            .controls-row {
                gap: 0.75rem;
            }

            .progress-container {
                height: 4px;
            }

            .volume-slider {
                width: 60px;
            }

            .mobile-sidebar-toggle {
                position: fixed;
                bottom: 2rem;
                right: 2rem;
                width: 56px;
                height: 56px;
                background: var(--accent-red);
                border: none;
                border-radius: 50%;
                color: white;
                font-size: 1.5rem;
                cursor: pointer;
                box-shadow: var(--shadow-medium);
                z-index: 200;
                transition: all 0.3s ease;
                display: flex;
                align-items: center;
                justify-content: center;
            }

            .mobile-sidebar-toggle:hover {
                transform: scale(1.1);
                background: #e60000;
            }

            /* 在移动端隐藏桌面版的侧边栏切换按钮 */
            .sidebar-toggle {
                display: none;
            }
        }

        /* 加载动画 */
        .loading-overlay {
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0, 0, 0, 0.7);
            display: flex;
            align-items: center;
            justify-content: center;
            z-index: 20;
        }

        .loading-spinner {
            width: 50px;
            height: 50px;
            border: 3px solid rgba(255, 0, 0, 0.3);
            border-top: 3px solid var(--accent-red);
            border-radius: 50%;
            animation: spin 1s linear infinite;
        }

        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }

        /* 手势提示 */
        .gesture-hint {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            color: white;
            font-size: 1.1rem;
            opacity: 0;
            transition: opacity 0.3s ease;
            pointer-events: none;
            text-align: center;
            background: rgba(0, 0, 0, 0.5);
            padding: 1rem 1.5rem;
            border-radius: var(--radius-md);
            backdrop-filter: blur(10px);
        }

        .video-container:hover .gesture-hint {
            opacity: 0.8;
        }

        /* 动画效果 */
        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }

        @keyframes slideInUp {
            from {
                transform: translateY(20px);
                opacity: 0;
            }
            to {
                transform: translateY(0);
                opacity: 1;
            }
        }

        .fade-in {
            animation: fadeIn 0.6s ease forwards;
        }

        .slide-in-up {
            animation: slideInUp 0.6s ease forwards;
        }

        /* 额外添加：确保导航栏中的文字在移动端也隐藏 */
        .nav-actions span {
            display: none;
        }