图片 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%);}

图片 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%);}