body{/*シェパードチェック柄*/
background-color:red;
background-image:
linear-gradient(-45deg,#000 25%,transparent 25%, transparent 75%,red 75%),
linear-gradient(135deg,#000 25%,transparent 25%, transparent 75%,red 75%),
linear-gradient(-45deg,#000 5%,transparent 5%,transparent 10%,#000 10%,#000 15%,transparent 15%,transparent 20%,#000 20%,#000 25%,transparent 25%,transparent 30%,#000 30%,#000 35%,transparent 35%,transparent 40%,#000 40%,#000 45%,transparent 45%,transparent 50%,#000 50%,#000 55%,transparent 55%,transparent 60%,#000 60%,#000 65%,transparent 65%,transparent 70%,#000 70%,#000 75%,transparent 75%,transparent 80%,#000 80%,#000 85%,transparent 85%,transparent 90%,#000 90%,#000 95%,transparent 95%);
background-size:40px 40px;
background-position:0 0,20px 20px,0 0;
}