<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style>
.center_box{
width: 80%;
height: 50%;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
</style>
</head>
<body>
<div class="center_box" style="border: 1px solid #f00; ">hhhhh</div>
</body>
</html>