Customizing comments.php and CSS

I have been tinkering with the comments.php page for a while now, and I’ve figured most of it out. I’ve been playing with the CSS as well, and again I’ve figured most of it out.

What I can’t figure out is which CSS variables affect the comments. I see the notation for comments in the style.css, but if I apply a background color, it doesn’t appear.

Any suggestions?

The webpage is:
http://greenshadow.com/id
The comments page is:
http://greenshadow.com/id/?p=60#comments
The style.css is:
http://greenshadow.com/id/wp-content/themes/moonchild/style.css

(I tried to play around with the stylesheet to get it to look right, so that should explain any superfluous variables.)