.backnumber {
	color:#036;
	font-weight:600;
	margin-bottom:1em;
	position: relative;
	background:#c1ffd0;
	padding: 0.2em 1em;
	border-radius: 6px;
}
.backnumber:after {
	content: "";
	position: absolute;
	top: 100%;
	left: 40px;
	height: 0;
	width: 0;
	border: 8px solid transparent;
	border-top: 8px solid #c1ffd0;
}


li.back,
li.back::before,
li.back::after {
	position: absolute;
	z-index: -1;
	display: block;
	content: '';
	-webkit-box-sizing: border-box;
	-moz-box-sizing: border-box;
	box-sizing: border-box;
	-webkit-transition: all .4s;
	transition: all .4s;
}
li.back {
	display: inline-block;
	text-align: center;
	text-decoration: none;
	outline: none;
	position: relative;
	z-index: 2;
	background-color: #c7f3ed;
	border: 1px solid #c7f3ed;
	color: #c7f3ed;
	overflow: hidden;
}
li.back:hover {
	color: #fff;
}
li.back::after {
	top: -100%;
	left: -100%;
	width: 100%;
	height: 100%;
}
li.back:hover::after {
	top: 0;
	left: 0;
	background-color: #fff;
}
ul.back {
	display: table;
	width:100%;
}
ul.back > li:nth-child(4n+1) {
	clear: both;
}
ul.back > li {
	display: table-cell;
	border-radius: 4px;
	margin:0.4em 1px;
	padding:0.5em 0;
	font-size : 0.9em;
	float: left;
	width: 24.3%;
}
/*================================================
 *  スマホ
 ================================================*/
ul.backnumber > li {
	font-size : 0.8em;
}