:root {
            --primary-color: #2c3e50;
            --secondary-color: #3498db;
            --accent-color: #e74c3c;
            --light-bg: #f9f9f9;
            --text-color: #333;
            --text-light: #7f8c8d;
        }
        
        body {
            font-family: 'Segoe UI', 'Microsoft YaHei', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.7;
            color: var(--text-color);
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
            background-color: var(--light-bg);
            background-image: linear-gradient(to bottom, rgba(255,255,255,0.9) 0%, rgba(255,255,255,0.8) 100%), 
                              url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="0 0 100 100" fill="none" stroke="%23e0e0e0" stroke-width="0.5"><path d="M0,0 L100,100 M100,0 L0,100"/></svg>');
        }
        
        header {
            background: linear-gradient(135deg, var(--primary-color) 0%, #1a252f 100%);
            color: white;
            padding: 40px 20px;
            border-radius: 8px;
            margin-bottom: 30px;
            text-align: center;
            box-shadow: 0 4px 12px rgba(0,0,0,0.15);
            position: relative;
            overflow: hidden;
        }
        
        header::after {
            content: "";
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: radial-gradient(circle at 75% 25%, rgba(255,255,255,0.1) 0%, transparent 70%);
            pointer-events: none;
        }
		
		a {
		  text-decoration: none;
		}
        
        h1 {
            margin: 0;
			text-align: center;
            font-size: 2.8em;
            font-weight: 700;
            letter-spacing: 1px;
            text-shadow: 1px 1px 3px rgba(0,0,0,0.3);
        }
        
        h2 {
            color: var(--primary-color);
            border-bottom: 3px solid var(--secondary-color);
            padding-bottom: 12px;
            margin-top: 50px;
            font-weight: 600;
            position: relative;
        }
        
        h2::after {
            content: "";
            position: absolute;
            bottom: -3px;
            left: 0;
            width: 100px;
            height: 3px;
            background: var(--accent-color);
        }
        
        h3 {
            color: var(--secondary-color);
            margin-top: 30px;
            font-weight: 600;
            padding-left: 10px;
            border-left: 4px solid var(--secondary-color);
        }
        
        p {
            margin-bottom: 20px;
            text-align: justify;
            font-size: 1.05em;
        }
        
        .section {
            background-color: white;
            padding: 30px;
            border-radius: 8px;
            box-shadow: 0 3px 10px rgba(0,0,0,0.08);
            margin-bottom: 35px;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            border: 1px solid rgba(0,0,0,0.05);
        }
        
        .section:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 15px rgba(0,0,0,0.12);
        }
		
		.sectiona {
            background-color: white;
            padding: 30px;
            border-radius: 8px;
            box-shadow: 0 3px 10px rgba(0,0,0,0.08);
            margin-bottom: 35px;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
            border: 1px solid rgba(0,0,0,0.05);
        }
        
        .sectiona:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 15px rgba(0,0,0,0.12);
        }
        
        table {
            width: 100%;
            border-collapse: separate;
            border-spacing: 0;
            margin: 25px 0;
            box-shadow: 0 2px 8px rgba(0,0,0,0.08);
            border-radius: 8px;
            overflow: hidden;
        }
        
        th, td {
            padding: 15px 18px;
            text-align: left;
            border-bottom: 1px solid rgba(0,0,0,0.05);
        }
        
        th {
            background: linear-gradient(to right, var(--secondary-color), #2980b9);
            color: white;
            font-weight: 600;
            text-transform: uppercase;
            font-size: 0.9em;
            letter-spacing: 0.5px;
        }
        
        tr:nth-child(even) {
            background-color: rgba(0,0,0,0.02);
        }
        
        tr:hover {
            background-color: rgba(52, 152, 219, 0.08);
        }
        
        .highlight {
            background: linear-gradient(to right, rgba(52, 152, 219, 0.05), rgba(52, 152, 219, 0.1));
            padding: 25px;
            border-left: 4px solid var(--secondary-color);
            margin: 25px 0;
            border-radius: 0 6px 6px 0;
            position: relative;
        }
        
        .highlight::before {
            content: "!";
            position: absolute;
            left: -15px;
            top: 50%;
            transform: translateY(-50%);
            width: 30px;
            height: 30px;
            background: var(--secondary-color);
            color: white;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
        }
        
        footer {
            text-align: center;
            margin-top: 60px;
            padding: 25px;
            color: var(--text-light);
            font-size: 0.95em;
            border-top: 1px solid rgba(0,0,0,0.1);
        }
        
        /* 折叠面板样式 */
        details {
            background-color: #f5f5f5;
            border-radius: 8px;
            margin: 15px 0;
            padding: 0;
            font-family: 'Arial', sans-serif;
            box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
            border: 1px solid rgba(0,0,0,0.05);
            overflow: hidden;
        }
        
        summary {
            padding: 15px 20px;
            background: linear-gradient(to right, var(--primary-color), #34495e);
            color: white;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            list-style: none;
            position: relative;
        }
        
        summary::-webkit-details-marker {
            display: none;
        }
        
        summary::after {
            content: "+";
            position: absolute;
            right: 20px;
            top: 50%;
            transform: translateY(-50%);
            font-size: 1.2em;
            transition: transform 0.3s ease;
        }
        
        details[open] summary::after {
            content: "-";
        }
        
        summary:hover {
            background: linear-gradient(to right, #0056b3, #1a5276);
        }
        
        /* 嵌套折叠样式 */
        details > details {
            margin-top: 15px;
            background-color: #e9ecef;
            box-shadow: none;
        }
        
        details > details summary {
            background: linear-gradient(to right, #28a745, #218838);
        }
        
        details > details summary:hover {
            background: linear-gradient(to right, #218838, #1e7e34);
        }
        
        details > div {
            padding: 20px;
        }

        
        /* 高亮遮盖效果 */
        .cover {
            cursor: pointer;
            background-color: rgba(128, 128, 128, 0.2);
            color: rgba(255, 0, 0, 0);
            display: inline-block;
            border-bottom: 2px solid var(--accent-color);
            padding: 0 2px;
            transition: all 0.3s ease;
            border-radius: 2px;
        }
		
		.math {
			display: inline-block;
			padding: 10px; 
			color: red;
			border-radius: 4px;
			cursor: pointer;
			font-size: 18px;
		}

        
        /* 列表样式 */
		ul {
			padding-left: 20px; /* 减少左边距 */
			list-style-type: none; /* 去除默认列表样式 */
		}

		li {
			margin-bottom: 10px;
			padding-left: 0; /* 去除左边距 */
		}
        
        li::before {
            color: var(--secondary-color);
            font-weight: bold;
            position: absolute;
            left: 0;
        }
		
		.p {
            margin-bottom: 10px;
            text-align: justify;
            font-size: 1.05em;
        }
        
        /* 响应式设计 */
        @media (max-width: 768px) {
            body {
                padding: 15px;
            }
            
            .section {
                padding: 20px;
            }
            
            h1 {
                font-size: 2.2em;
            }
            
            th, td {
                padding: 12px 15px;
            }
        }
		
		.button-container {
            position: fixed;
            bottom: 10px;
            left: 10px;
            display: flex;
            flex-direction: row; /* 将按钮垂直排列 */
           
        }

        .button-container button {
            padding: 10px;
            background-color: #fff;
            border: none;
            border-radius: 5px;
            cursor: pointer;
        }