[tpearl5]

FYI, for anyone that is only showing ads based on permissions in the vbulletin ad system, this is a better solution (in combination with the above css) so you do not show the box without an ad in it:

<vb:if condition="$show['first_ad'] AND $post['isfirstshown']">
<li class="firstpost_advert_container"><div class="firstpost_advert">
	{vb:raw ad_location.thread_first_post_content}
</div></li>
</vb:if>
<vb:if condition="$show['last_ad'] AND $post['islastshown']">
<li class="firstpost_advert_container"><div class="firstpost_advert">
	{vb:raw ad_location.thread_last_post_content}
</div></li>
</vb:if>

There's no sense in loading two sets of CSS for the ads unless you want them to look different.