.nav {
    list-style: none;
    display: flex;
    font-size: 21px;
    font-family: 'STZhongsong', serif;
    z-index: 99;
}

.nav>li {
    position: relative;
}

.nav li a {
    display: block;
    padding: 15px 25px;
    text-decoration: none;
    color: #333;
    transition: all 0.3s;

}

.nav>li>a:hover {
    background: #f8f8f8;
    color: #007bff;
}

/* 二级菜单 */
.submenu {
    position: absolute;
    top: 100%;
    left: 0;
    background: #fff;
    min-width: 200px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    border-radius: 6px;
}

.nav>li:hover .submenu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.nav > li.selected>a {
    color: white;
}
.nav > li.selected>a {
     background-color:#ff8080;
}


.submenu li {
    border-bottom: 1px solid #eee;
    list-style-type: none;
}

.submenu li:last-child {
    border-bottom: 0;
}

.submenu li a {
    padding: 12px 20px;
    transition: background 0.2s;
    position: relative;
    /* 添加相对定位 */
}

.submenu li a:hover {
    background: #f8f8f8;
    padding-left: 25px;
}

.submenu li a::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 2px;
    /* 下划线的高度 */
    background-color: red;
    /* 下划线的颜色 */
    left: 0;
    bottom: 0;
    transform: scaleX(0);
    /* 初始状态下隐藏下划线 */
    transition: transform 0.3s ease;
    /* 添加过渡效果 */
}

.submenu li a:hover::after {
    transform: scaleX(1);
    /* 悬停时显示下划线 */
}

/* 移除默认的箭头样式 */
.nav>li>a::after {
    content: none;
}

/* 添加新的箭头样式规则，仅在有子菜单时显示箭头 */
.nav>li.has-submenu>a::after {
    content: "";
    display: inline-block;
    margin-left: 8px;
    vertical-align: middle;
    border: 5px solid transparent;
    border-top-color: #999;
    transition: transform 0.3s;
}

.nav>li:hover>a::after {
    transform: rotate(180deg);
}

.section {
    text-align: center;
    font: 50px "Microsoft Yahei";
    color: black;
    background: #fff;
    padding-top: 60px;
    /* 确保section内容不会被固定的header遮挡 */
}

.section p {
    font: 30px "Microsoft Yahei";
}


.footersection {
    text-align: center;
    font: 20px "Microsoft Yahei";
    color: black;
    background: #fff;
}   
.footersection p {
    font: 30px "Microsoft Yahei";
}