/* 页眉样式 */
        header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            padding: 20px 50px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            z-index: 1000;
            transition: 0.5s;
        }
        
        header.transparent {
            background: rgba(255, 255, 255, 0.1);
            backdrop-filter: blur(10px);
            border-bottom: 1px solid rgba(255, 255, 255, 0.2);
        }
        
        header.scrolled {
            background: rgba(255, 255, 255, 0.95);
            box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
            padding: 15px 50px;
        }
        
        .logo {
            font-size: 1.8rem;
            font-weight: 700;
            color: #2c3e50;
            text-decoration: none;
        }
        
        .logo span {
            color: #3498db;
        }
        
        nav ul {
            display: flex;
            list-style: none;
        }
        
        nav ul li {
            margin-left: 30px;
        }
        
        nav ul li a {
            text-decoration: none;
            color: #2c3e50;
            font-weight: 500;
            font-size: 1.1rem;
            padding: 8px 0;
            position: relative;
            transition: 0.3s;
        }
        
        header.transparent nav ul li a {
            color: #fff;
            text-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
        }
        
        nav ul li a:hover {
            color: #3498db;
        }
        
        nav ul li a::after {
            content: '';
            position: absolute;
            width: 0;
            height: 2px;
            background: #3498db;
            bottom: 0;
            left: 0;
            transition: 0.3s;
        }
        
        nav ul li a:hover::after {
            width: 100%;
        }
        
        /* 移动端菜单样式 */
        .menu-toggle {
            display: none;
            cursor: pointer;
            font-size: 2rem;
            color: #002FA7;
        }
        
        /* 响应式设计 */
       @media (max-width: 768px) {
    header {
        padding: 20px 30px;
    }
    
    header.scrolled {
        padding: 15px 30px;
    }
    
    .menu-toggle {
        display: block;
    }
     .logo {
            font-size: 1.2rem;
            font-weight: 700;
            color: #2c3e50;
            text-decoration: none;
        }
    nav {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: rgba(0, 0, 0, 0.95); /* 改为半透明黑色背景 */
        backdrop-filter: blur(10px);
        box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
        padding: 0;
        max-height: 0;
        overflow: hidden;
        transition: 0.5s;
    }
    
    nav.active {
        max-height: 300px;
        padding: 20px 0;
    }
    
    nav ul {
        flex-direction: column;
        align-items: center;
    }
    
    nav ul li {
        margin: 10px 0;
    }
    
    nav ul li a {
        color: #fff; /* 确保导航文字为白色 */
        font-size: 1.1rem;
        padding: 8px 20px;
    }
    
    /* 移除或修改透明头部的特殊样式 */
    header.transparent nav {
        background: rgba(0, 0, 0, 0.85); /* 统一使用半透明黑色 */
        backdrop-filter: blur(10px);
    }
    
    header.transparent nav ul li a {
        color: #fff; /* 确保文字为白色 */
    }
}
          /* 内容区域样式 */
        .content {
            max-width: 1200px;
            margin: 100px auto;
            padding: 0 20px;
        }
        
        .section {
            margin-bottom: 80px;
        }
        
        .section h2 {
            font-size: 2.5rem;
            margin-bottom: 30px;
            color: #2c3e50;
            text-align: center;
        }
        
        .section p {
            font-size: 1.1rem;
            line-height: 1.8;
            color: #34495e;
            margin-bottom: 20px;
        }