body{/*七宝(中に星)柄の背景*/
background-size:20px 20px;
background-position:10px 10px,0 0;
background-image:
radial-gradient(transparent 10px,#fff 10px,#fff 12px,transparent 12px),
radial-gradient(#006 10px,#fff 10px,#fff 12px,#006 12px);
}