CSS for articles

I am not sure if this forum is for asking questions, but I will try.

I am not a CSS expert. I assume that CSS can help format the articles. As far as I can tell, we cannot create CSS for articles we write; that is, we do not have access to the style tag. If there is a way to put CSS or an equivalent into articles, then I have not seen it and I look at the articles every day.

I tried looking at the CSS that is available to articles and there is a long list of styles but most of them seem to be for the page that articles are in but not the articles themselves. If I know more about CSS, then can I determine what CSS is available for auhors for use in articles? If not, then is there some documentation someplace of that? If not, then I think it would help to have that.

The Editor control we use having limited options only. But still the Editor control having "Insert DIV" icon we can apply css class, but the same must be available on our server. Might Mahesh can check this out.