Ok, I got it working. Weird but I had to put this at the TOP of my extra.css cause at the bottom it doesn't work. Something must be broken within.
and how to add icon for "Unlike"?
.item.control.unlike:before
{
content: "YOUR ICON";
display: inline-block;
font-family: FontAwesome;
font-size: inherit;
text-rendering: auto;
-webkit-font-smoothing: antialiased;
margin-right: 3px;
}