.back_to_top {
	display: none;
	position: fixed;
	_position: absolute;
	bottom: 110px;
	left: 50%;
	margin-left: 600px;
	/* right: 0;
	z-index: 100; */
	
}

.back_to_top a {
	display: block;
	width: 52px;
	height: 52px;
	background-image: url(../img/aboutus/backToTop.png);
	opacity: .5;
	background-repeat: no-repeat;
	-webkit-transition: background-image .3s, opacity .3s;
	transition: background-image .3s, opacity .3s
}

.back_to_top a:hover {
	opacity: 1
}