效果图：
二级导航：
源码：
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="./css/000.css" /><!-- 初始化样式 -->
<title>博物馆</title>
<style>
*{
transition: all 0.5s;
}
header {
background-color: rgb(157, 58, 32);
}
body{
background-color: #6778811;
}
#nav {
display: flex;
/*横向排布*/
justify-content: space-between;
list-style-type: none;
}
#nav li {
flex: 1;
box-sizing: border-box;
height: 60px;
line-height: 60px;
position: relative;
/* border: 2px solid #000; */
/* width: 320px; */
text-align: center;
position: relative;
}
#nav li:hover {
transition: all 0.35s;
background-color: rgb(177, 58, 32);
}
#nav li a {
text-decoration: none;
color: #fff;
}
.wrap {
width: 1280px;
margin: 0 auto;
}
#nav li .seclist {
width: 100%;
position: absolute;
top: 60px;
left: 0;
background-color: brown;
opacity: 0;
overflow: hidden;
/* 其他样式保持不变 */
transition: opacity 1s;
/* 添加过渡效果 */
}
#nav li:hover .seclist {
/* display: block; */
/* animation: navlist 1s; */
opacity: 1;
}
#nav li .seclist :hover {
background-color: aqua;
}
#nav li .seclist :hover a {
color: orange;
}
.banner {
height: 100%;
}
@keyframes navlist {
from {
display: none;
}
to {
display: block;
}
}
#main .wrap img {
height: 100%;
width: auto;
}
.left,
.banner {
margin: 50px auto;
float: left;
}
#main .left {
width: 200px;
height: 100%;
background-color: antiquewhite;
}
#main .wrap {
height: 700px;
}
</style>
</head>
<body>
<header>
<div class="wrap">
<ul id="nav">
<li><a href="./index.html">首页</a></li>
<li>
<a href="./index.html">
博物馆历史
<ul class="seclist">
<li><a href="./index.html">明清时期</a></li>
<li><a href="./index.html">民国时期</a></li>
</ul>
</a>
</li>
<li>
<a href="./index.html">
展览品概览
<ul class="seclist">
<li><a href="./index.html">青铜器</a></li>
<li><a href="./index.html">农具</a></li>
</ul>
</a>
</li>
<li>
<a href="./index.html">
线上订票
<ul class="seclist">
<li><a href="./index.html">A区</a></li>
<li><a href="./index.html">B区</a></li>
</ul>
</a>
</li>
</ul>
</div>
</header>
<div id="main">
<div class="wrap">
<div class="left"></div>
<div class="banner">
<img src="https://fd.co188.com/group2/M01/3B/A8/rBJhbGXwYDWAUUqDAAHZTr0PwYY72.jpeg" alt="" />
</div>
</div>
</div>
</body>
</html>
