http://stackoverflow.com/questions/27492191/how-to-make-a-fancy-arrow-using-css
display: inline-block;
border-left: 4px solid transparent;
border-right: 4px solid transparent;
border-top: 5px solid black;
width: 0;
height: 0;
margin-top: -1px;
margin-left: 6px;
margin-right: -14px;
vertical-align: middle;