<!DOCTYPE html>
<html>
<head>
<title>旋转</title>
</head>
<style>
.bg{
width: 200px;
height: 200px;
margin: 10px;
border-radius: 50%;
text-align: center;
box-shadow: 0 1px 8px #666;
}
.bg:hover{
transition: all 0.5s ease-in;
transform:rotate(360deg);
}
</style>
<body>
<div class="bg">旋转吧</div>
</body>
</html>