没有效果，老师看一下

来源：3-4 行为层

lhebe

2019-03-04 09:58:57

<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<link href="cs.css" rel="stylesheet" type="text/css">
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript" src="js/js.js"></script>
</head>
<body>
<span></span>
<nav>
<a href="">fdfd</a>
<a href="">sd</a>
<a href="">sdf</a>
<a href="">sdf</a>
<a href="">sdf</a>
</nav>
<div >
<img src="img1/bg1.jpg" alt=""/>
<img src="img1/bg2.jpg" alt=""/>
<img src="img1/bg3.jpg" alt=""/>
<img src="img1/bg2.jpg" alt=""/>
<img src="img1/bg3.jpg" alt=""/>
</div>
</body>
</div>

</html>

*{
margin:0;
padding:0;
borde:none;
}
body{
background: #7c7d7d;;
}
span{
display: block;
width:20px;
height:20px;
border-radius: 50%;
background: #ffffff;
margin:20px auto;
}
nav{
margin:20px auto 10px;
position: relative;
width:78.125vw;
display: flex;
justify-content: space-between;
}
nav:before{
width:100%;
height:10px;
position: absolute;
background: #ffffff;
top:20px;
display: block;
content:''; //显示内容
}
nav > a{

position: relative;
font-size:20px;
text-decoration: none;
padding:10px;
border:2px solid #5395b4;
color:#fff;
background: #255d7e;
}
div{
position: relative;
width:78.125vw;
height:75vh;
margin:40px auto 0;
overflow: hidden;
background: paleturquoise;
box-shadow: 0 0 30px 0 rgba(8,1,1,0.3);
}
div > img{

width:98%;
height:96%;
position:absolute;
top:0px;
right:0;
bottom:0;
left:0px;
margin:auto;
left:2px;

}