*{
margin: 0;
padding: 0;
}
li{
list-style-type: none;
}
a{
text-decoration: none;
}
.ul1{
margin: 50px;
}
.ul1>li{
150px;
height: 2em;
border-radius: 0.5em 0.5em 0 0;
background: rgba(30,80,200,0.8);
font-size: 20px;
line-height: 2em;
text-align: center;
float: left;
margin-left: 20px;
}
.ul2{
background: rgba(80,80,160,0.6);
border-radius: 0 0 0.5em 0.5em;
display: none;
}
.ul2>li>a:hover{
background: rgba(140,180,40,0.8);
85%;
height: 1.5em;
line-height: 1.5em;
display:inline-block;
border-radius: 0.5em;
font-weight: bold;
padding: 3px 3px;
}
.ul1>li:hover>ul{
display: block;
}
.ul1>li:hover{
background: rgba(30,80,250,0.8);
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>下拉菜单</title>
<link rel="stylesheet" href="style9.css" type="text/css">
</head>
<body>
<nav>
<ul class="ul1">
<li><a href="">首页</a>
<ul class="ul2">
<li><a href="">新闻</a></li>
<li><a href="">科技</a></li>
<li><a href="">财经</a></li>
<li><a href="">读书</a></li>
</ul>
</li>
<li><a href="">首页</a>
<ul class="ul2">
<li><a href="">新闻</a></li>
<li><a href="">科技</a></li>
<li><a href="">财经</a></li>
<li><a href="">读书</a></li>
</ul>
</li>
<li><a href="">首页</a>
<ul class="ul2">
<li><a href="">新闻</a></li>
<li><a href="">科技</a></li>
<li><a href="">财经</a></li>
<li><a href="">读书</a></li>
</ul>
</li>
</ul>
</nav>
</body>
</html>