@charset "UTF-8";
body {
	background: #eee;
}
#box {
	width: 590px;
	margin: 0 auto;
	background: #transparent;
	}


#box .bt {
	position: relative;
	text-align: center;

}

.bt a:before {
	content: "";
	width: 100px;
	height: 76px;
	display: inline-block;
	background-image: url(images/arrow.png);
	background-size: 100% 100%;
	position: absolute;
	left: 0px;
	animation: arrow_anim alternate infinite 0.5s ease;
	top: 50%;
	margin-top: -44px;
}

.bt img {
width: 539px;
}

@keyframes arrow_anim{
	0%{transform:translate(0,0)}
	100%{transform:translate(-20px,0)}
}