<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>css叠加性和层叠性</title>
<style type="text/css">
nav{width:600px; height:30px;background:gray;margin:100px auto}
nav div{width:100px; height:40px;link-height:40px;
float:left;color:#ffffff;text-align:center;}
nav div:hover{color:blue;font-size:18px}
</style>
</head>
<body>
<nav>
<div>冲压件</div>
<div>注塑件</div>
<div>排针</div>
<div>排母</div>
<div>wafer</div>
<div>D-sub</div>
</nav>
</body>
</html>
返回：
鼠标移动到上面会变蓝色：