something like this
Code:
{ include file="meta.tpl" }
{if $cat eq 1}
<LINK rel="stylesheet" href="{$SkinDir}/skin1.css">
{elseif $cat eq 2}
<LINK rel="stylesheet" href="{$SkinDir}/skin2.css">
{elseif $cat eq 3}
<LINK rel="stylesheet" href="{$SkinDir}/skin3.css">
{elseif $cat eq 4}
<LINK rel="stylesheet" href="{$SkinDir}/skin4.css">
{else}
<LINK rel="stylesheet" href="{$SkinDir}/skin1.css">
{/if}
</HEAD>