.arrows {
	width: 60px;
	height: 72px;
	display:block;
	margin:.5rem auto;
}

.arrows path {
	fill: transparent;
	stroke-width: 1px;	
	animation: arrow 2s infinite;
	-webkit-animation: arrow 2s infinite; 
}

@keyframes arrow
{
0% {opacity:0}
40% {opacity:1}
80% {opacity:0}
100% {opacity:0}
}

@-webkit-keyframes arrow /*Safari and Chrome*/
{
0% {opacity:0}
40% {opacity:1}
80% {opacity:0}
100% {opacity:0}
}

.arrows path.a1 {
	animation-delay:-1s;
	-webkit-animation-delay:-1s; /* Safari 和 Chrome */
}

.arrows path.a2 {
	animation-delay:-0.5s;
	-webkit-animation-delay:-0.5s; /* Safari 和 Chrome */
}

.arrows path.a3 {	
	animation-delay:0s;
	-webkit-animation-delay:0s; /* Safari 和 Chrome */
}