效果图：
代码：<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div{
overflow: hidden;
width: 150px;
height: 150px;
border: 1px solid pink;
margin: 10px 10px;
float: left;
}
div::after{
content: "许";
display: block;
width: 100%;
height: 100%;
background-color: aqua;
transform: rotate(180deg);
transform-origin: left bottom;
transition: all .5s;
}
div:hover::after{
transform: rotate(0deg);
}
</style>
</head>
<body>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
</body>
</html>
