<!DOCTYPE html>
<html>
<head>
<title></title>
<meta charset="utf-8">
<style type="text/css">
*{
margin: 0;
padding: 0;
}
.page{
width: 100%;
height: 4000px;
background-color: yellow;
}
.nav{
width: 160px;
height: auto;
position: fixed;
left: 0;
top: 50%;
margin-top:-103px ;
}
.nav-li{
width: 160px;
height: 40px;
border-bottom: 1px solid #fff;
text-align: center;
line-height: 40px;
color: #fff;
font-size: 16px;
background-color: #333;
}
.nav-li ul{
width: 160px;
height: auto;
}
.nav-li ul li{
width: 160px;
height: 40px;
border-bottom: 1px dashed #666;
color: #333;
text-align: center;
line-height: 40px;
background-color: white;
}
</style>
</head>
<body>
<div class="page">
<div class="nav">
<div class="nav-li">
<div class="tit">标题</div>
<ul>
<li>二级栏目</li>
</ul>
</div>
<div class="nav-li">标题</div>
<div class="nav-li">标题</div>
<div class="nav-li">标题</div>
<div class="nav-li">标题</div>
</div>
</div>
</body>
</html>