Re: detail of Style.css ?
I _highly_ recommend you get hold of the Web Devloper Toolbar for Firefox  – it will enable you to answer all these questions for yourself, and actively experiment with the CSS, in a “change-it-&-see-it-instantly” way.
It has two very useful features:
1 – you can hit Ctrl+F and point to any item in screen to see what it’s CSS class and id are
2 – hit Ctrl+E and you can edit the css live, so you can see “what would happen if it changed…”
All you need do then is copy your edited CSS and use it to update the version on your server. It makes investigation and tweaking very easy.