[Mediawiki-l] css changes

[sitebuil]

I have played with some css to change text size and line spacing for 
when I want to project a page for my class. The monobook.css looks like 
this:

p
{
font-size: 150%;
line-height: 250%;
}

h1,h2,h3,h4,li {font-size: 150%;}

This works but I'd like to limit the changes in appearance to just the 
article, or body or content  area. I've looked at the html source and I 
see that the <div tag has disfferent classes and id's Is there a way to 
limit the .css modifications to the content area?