If you can have the feed display IN your page, like, as text/links or whatever, just wrap the part that does the feed work with a div:
<div class="xml-feed">
feed stuff
</div>
Then in your css file, just give each element in the div a style:
.xml-feed
{
stuff
}
.xml-feed p
{
paragraph styles
}
.xml-feed a:link, .xml-feed a:visited, .xml-feed a:active
{
link styles
}
etc...
The real hell is your life gone wrong.