// in the header, where you call the css, do this instead.

<ss:if test="$string.matches($page.bodyTemplate.name, '^(c(art|heckout(pro|-anon)?|ontact)|invoice|billing|orderconfirm|shipto(gift)?)$')"><ss:else/>
<ss:thisistotallyhowyoucallacssfile/>
</ss:if>

// and in the footer, add this line.

<ss:if test="$string.matches($page.bodyTemplate.name, '^(c(art|heckout(pro|-anon)?|ontact)|invoice|billing|orderconfirm|shipto(gift)?)$')">
<ss:thisistotallyhowyoucallacssfile/>
</ss:if>