XF 1.2 Adding a little arrow to the top of popup menu

[Helixion]

So I'm attempting to add a little arrow to "distinguish" the popup menus.

here's a good example:

Cyrodiil.net

.Menu:before
{

border-top: 15px solid #61513b;
border-right: 15px solid transparent;
transform:rotate(45deg);
-ms-transform:rotate(45deg); /* IE 9 */
-webkit-transform:rotate(45deg);
content: "";
display: block;
height: 0;
position: absolute;
right: 5px;
top: 0px;
width: 0;
clear: both;

}
Unfortunately It doesn't go past the box, which means I have to attach the :before to a different container.