<!DOCTYPE html>
<html lang="ch">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
*{
margin: 0;
padding: 0;
}
.kuai{
width: 200px;
height: 200px;
border: red solid 1px;
position: absolute;
right: 0;
left: 0;
top:0;
bottom:0;
margin: auto;
}
.cirle2{
width: 200px;
height: 200px;
border: red solid 1px;
border-radius: 50%;
position: absolute;
top:50%;
left: 50%;
transform:translate(-50%,-50%);
margin-right: 50%;
}
</style>
</head>
<body>
<div class="kuai">
<div class="cirle2"></div>
</div>
</body>
</html>
