/* 基础重置与响应式设置 */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, sans-serif;
        }
        :root {
            --header-bg: #2c3e50;
            --sidebar-bg: #34495e;
            --content-bg: #ecf0f1;
            --text-light: #fff;
            --text-dark: #333;
        }

        /* 响应式网格系统 */
        .container {
            display: flex;
            flex-wrap: wrap;
            min-height: 100vh;
        }

        /* 顶部导航栏（居中标题） */
        .header {
            background: var(--header-bg);
            color: var(--text-light);
            text-align: center;
            padding: 0.8rem 1.2rem;
            width: 100%;
            box-shadow: 0 2px 10px rgba(0,0,0,0.2);
            position: relative;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
        }
	.header a {
            text-decoration: none;
            color: white;
	}
        .header-titles {
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        .header-title {
            font-size: 1.5rem;
            line-height: 1.3;
        }
        .header-subtitle {
            font-size: 0.75rem;
            font-weight: normal;
            opacity: 0.8;
            margin-top: 0.2rem;
            letter-spacing: 0.5px;
        }

        /* 左侧目录导航 */
        .sidebar {
	    overflow-y: auto;
	    height: 100vh;
            background: var(--sidebar-bg);
            color: var(--text-light);
            width: 280px;
            padding: 1rem;
            transition: transform 0.3s ease;
        }
        .sidebar a {
	    text-decoration: none;
	    color: white;
	}
        .chapter-list {
            list-style: none;
            max-height: calc(100vh - 70px);
            overflow-y: auto;
        }
        .chapter-item {
            padding: 5px 10px;
            border-bottom: 1px solid rgba(255,255,255,0.1);
            cursor: pointer;
            transition: background 0.2s;
        }
        .chapter-item:hover {
            background: rgba(0,0,0,0.2);
        }

        /* 主内容区域 */
        .main-content {
            flex: 1;
            padding: 2rem;
            background: var(--content-bg);
            min-height: calc(100vh - 70px);
        }
        .content-section {
            line-height: 1.8;
            font-size: 1.1rem;
        }

        /* 移动端适配 */
        @media (max-width: 768px) {
            .sidebar {
                position: fixed;
                height: 100vh;
                z-index: 90;
                transform: translateX(-100%);
            }
            .sidebar.active {
                transform: translateX(0);
            }
            .menu-toggle {
                display: block;
                position: absolute;
                top: 1.2rem;
                left: 1rem;
                color: white;
                font-size: 1.5rem;
                cursor: pointer;
            }
            .main-content {
                padding: 1.5rem;
            }
            .header {
                padding-top: 1.5rem;
                padding-bottom: 1.0rem;
            }
        }

        /* 电脑端优化 */
        @media (min-width: 769px) {
            .menu-toggle {
                display: none;
            }
        }