Editing the Content ID

Good day, I am attempting to insert an image in the #content ID of the style.css. As you probably already guessed, it's not working out for me too well. :P My code: <code> #content { background: url("images/fish-net.jpg") repeat !important; margin: 0 38.6% 0 3%; width: 58.4%; } </code> I added the background, of course. Now if I read the HTML correctly, the content should be the space between the nav and footer, under the page boxes, and comment boxes, and widget boxes?   Any help would be appreciated!