Change Tooltip Style of qtip2

HTML

<script src="http://craigsworks.com/projects/qtip2/packages/latest/jquery.qtip.min.js"></script>
<link rel="stylesheet" href="http://craigsworks.com/projects/qtip2/packages/latest/jquery.qtip.min.css">
<a href="#" id="tip">Tooltip for that</a><br>
<a href="#" id="r">RED</a> - <a href="#" id="b">BLUE</a>

JavaScript

$(function() {
    $("#tip").qtip({
    content: {
        text: "Test"
        }});
    $("#r").click(function() {
        $("#tip").qtip('option', 'style.classes', 'ui-tooltip-red');
    });
    $("#b").click(function() {
        $("#tip").qtip('option', 'style.classes', 'ui-tooltip-blue');
    });
});