body{/*杉綾*/
background-size:40px 40px;
background-position:0 0,20px 20px,20px 0,0 20px;
background-image:
linear-gradient(-45deg,#fff 25%,transparent 25%),
linear-gradient(-135deg,#fff 25%,transparent 25%),
linear-gradient(135deg,#fff 25%,transparent 25%),
linear-gradient(45deg,#fff 25%,#ecf 25%);
}