<a href="#" class="buttonDownload">Download</a>

body {
	background-color: #1a1a1a;
}

.buttonDownload {
	display: inline-block;
	position: relative;
	padding: 10px 25px;
  
	background-color: #4CC713;
	color: white;
  
	font-family: sans-serif;
	text-decoration: none;
	font-size: 0.9em;
	text-align: center;
	text-indent: 15px;
}

.buttonDownload:hover {
	background-color: #333;
	color: white;
}

.buttonDownload:before, .buttonDownload:after {
	content: ' ';
	display: block;
	position: absolute;
	left: 15px;
	top: 52%;
}

/* Download box shape  */
.buttonDownload:before {
	width: 10px;
	height: 2px;
	border-style: solid;
	border-width: 0 2px 2px;
}

/* Download arrow shape */
.buttonDownload:after {
	width: 0;
	height: 0;
	margin-left: 3px;
	margin-top: -7px;
  
	border-style: solid;
	border-width: 4px 4px 0 4px;
	border-color: transparent;
	border-top-color: inherit;
	
	animation: downloadArrow 2s linear infinite;
	animation-play-state: paused;
}

.buttonDownload:hover:before {
	border-color: #4CC713;
}

.buttonDownload:hover:after {
	border-top-color: #4CC713;
	animation-play-state: running;
}

/* keyframes for the download icon anim */
@keyframes downloadArrow {
	/* 0% and 0.001% keyframes used as a hackish way of having the button frozen on a nice looking frame by default */
	0% {
		margin-top: -7px;
		opacity: 1;
	}
	
	0.001% {
		margin-top: -15px;
		opacity: 0;
	}
	
	50% {
		opacity: 1;
	}
	
	100% {
		margin-top: 0;
		opacity: 0;
	}
}