Xenforo: If there are new posts, make this button orange

Question

I have a little problem, I'm trying to figure out how to make a certain button turn orange whenever there are new posts, however I can't get it done.

This is my code right now:

.xbUserPanelBox .xbUserPanelMenus .newPosts .navLink
{
@property "xb_user_panel_new_posts";
<xen:if is="{$thread.isNew} AND {$thread.haveReadData}">color: rgb(255, 128, 0);
<xen:else />color: white;</xen:if>
@property "/xb_user_panel_new_posts";
}

If anyone could help, it would be appriciated.