Hereinafter is the list of the well known cascading style sheets created by Opera, W3C org and others. Enjoy.
Choose any style from drop-down combo box bellow; enter any (correct) URL in the form-field (try w3.org for example) and submit. If URL is omitted, CSS will be attached to this page; the same with links in CSS creators section. Maybe you'll find this play useful, maybe not but [imho] it is in tough relation with document structure.
Nice of course and it is perfectly clear that as document mark-up (structure) is better, page with ‘alien’ CSS looks more nice or acceptable but... also very important fact is that each single CSS is created for author's own purpose, for his own mark-up way and fables or myths about ‘universal style sheets’ are nothing else then tales for kids for ‘cold, blowy nights in early April’.:)