<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="X-UA-Compatible" content="ie=edge" />
<title>Document</title>
<style type="text/css">
*{
margin: 0;
padding: 0;
}
.box1{
width: 300px;
height: 300px;
background-color: #003399;
position: relative;
}
p{
color: #FFFFFE;
font-size: 20px;
margin: 0;
padding: 0;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50% ,-50%);
}
</style>
</head>
<body>
<div class="box1">
<p>垂直居中</p>
</div>
</body>
</html>