* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;}
        
        ul {
            list-style: none;}
        
        .nav-container {
            width: 100%;
            position: relative;
            max-width: 1400px;
            font-size: 18px;}
        
        /* 一级导航样式 */
        .nav-primary {
            width: 100%;
            display: flex;
            justify-content: space-between;
            margin: 0 auto;
            position: relative;}
        
        .nav-primary > li {
            position: relative;
            flex: 1;
            text-align: center;
            padding: 20px;
            cursor: pointer;
            transition: all 0.3s ease;}
        
        .nav-primary > li:hover {
            color: #0078d7;}
        
        /* 二级导航样式 */
        .nav-secondary {
            display: none;
            position: absolute;
            top: 100%;
            left: 50%;
            transform: translateX(-50%);
            background-color: white;
            padding: 10px 0;
            border: 1px solid #ccc;
            border-top: none;
            border-bottom-left-radius: 5px;
            border-bottom-right-radius: 5px;
            z-index: 10;
            box-shadow: 0 2px 10px rgba(0,0 , 0, 0.1);}
        
        .nav-primary > li:hover .nav-secondary {
            display: block;}
        
        .nav-secondary > li {
            padding: 8px 15px;
            transition: background-color 0.3s ease;}
        
        .nav-secondary > li:hover {
            background-color: #f0f0f0;}
        
        /* 二级使导航宽度自适应文本长度 */
        .nav-secondary {
            width: auto;
            white-space: nowrap;}
        
        .nav-secondary > li {
            width: 100%;}