body{/*立方体を敷き詰めた背景*/
background-size:50px 86.6px;
background-color:#999;
background-image:
linear-gradient(30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%,#fff),
linear-gradient(-30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%,#fff),
linear-gradient(30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%,#fff),
linear-gradient(-30deg,#fff 12.5%,transparent 12.5%,transparent 87.5%,#fff 87.5%,#fff),
linear-gradient(60deg, #ccc 25%,transparent 25%,transparent 75%,#ccc 75%,#ccc),
linear-gradient(60deg, #ccc 25%,transparent 25%,transparent 75%,#ccc 75%,#ccc);
background-position:0 0,0 0,25px 43.3px,25px 43.3px,0 0,25px 43.3px;}