<!DOCTYPE html>
<html lang="en">
<head>
<title></title>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="css/style.css" rel="stylesheet">
<style>
* {
margin: 0;
}
.mask {
background-color: #7b7070;
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 0;
width: 100%;
height: 100%;
}
.box {
position: absolute;
top: 50%;
margin-top: -100px;
background-color: #fff;
height: 200px;
width: calc(100% - 50px); //这里是水平居中的关键 margin-left = 50/2
margin-left: 25px;
text-align: center;
border-radius: 5px;
}
</style>
</head>
<body>
<div>
<div class="mask"></div>
<div class="box">
<p>title</p>
</div>
</div>
</body>
</html>