<!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>
*{
margin: 0;
padding: 0;
}
.box1{
width: 100vw;
height: 100vh;
background-color: #bfa;
display: table-cell;
vertical-align: middle;
}
.box2{
width: 200px;
height: 200px;
margin: auto;
background-color:skyblue;
}
</style>
</head>
<body>
<div class="box1">
<div class="box2"></div>
</div>
</body>
</html>
