CSS help

[Cheikh Sow]

guys I have a problem I am doing a web site where I dont have
access to the CSS file. But the site content is written entirely
using tables many of them. There is a left navigation width
=182, right navigation width=162, but nothing is there unless
you put something in it and a content (.body_copy)that is 97%.
As I can tell the content itself can be divided with content_left width=228
and content_right=remaining_content
What I notice is in the CSS code there is no dimension given for
width.
So my question is is it possible to redefine the .body_copy to give
it a width and create another class and give it a width of 228?
Note .body_copy and content_left should be parallels
Right now this is the content's CSS
.yellow_body {
background-color: #FFFFCC;
font-family: Arial, Helvetica, sans-serif;
font-size: 90%;
color: #000000;
padding: 5px;
border-bottom-width: 1px;
border-bottom-style: solid;
border-bottom-color: #000066;
}
.body_copy {
font-family: Arial, Helvetica, sans-serif;
font-size: 90%;
color: #000000;
padding: 5px;
}

[Eric Pascarello]

It is valid to have multiple rules for things

foo{ color: #345345; }
foo{ background-color: #CCCCCC; }

Eric

[Paul Clapham]

... and they don't have to be in the same CSS file, either.