body{/*立方体を敷き詰めた背景*/
background-color:#cde;
background-size:52px 90px;
background-position:0 0,0 0,26px 45px,26px 45px,0 0,26px 45px;
background-image:
linear-gradient(30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%),
linear-gradient(-30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%),
linear-gradient(30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%),
linear-gradient(-30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%),
linear-gradient(-60deg, rgba(0,0,0,.2) 25%,transparent 25%,transparent 75%,rgba(0,0,0,.2) 75%),
linear-gradient(-60deg, rgba(0,0,0,.2) 25%,transparent 25%,transparent 75%,rgba(0,0,0,.2) 75%);
}