<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>图片</title>
<style>
div{height: 400px;width: 400px;background-size: 40px 40px; background-image: linear-gradient(45deg, #555 25%,transparent 25%,transparent 75%, #555 75%),linear-gradient(135deg,#555 25%,transparent 25%,transparent 75%, #555 75%);}
</style>
</head>
<body>
<div></div>
</body>
</html>