body { background-color: #fdfdfd; /*背景の格子色*/ background-image: linear-gradient( transparent 95%, rgba(0, 0, 0, .06) 50%, rgba(0, 0, 0, .06)), linear-gradient( 90deg, transparent 95%, rgba(0, 0, 0, .06) 50%, rgba(0, 0, 0, .06) ); background-size: 25px 25px; background-repeat: repeat; width:100%; heig…