You want to change the background color on that page? You have this:
HTML Code:
.body_wrapper {background-color: transparent;}
So that background is coming from here:
HTML Code:
html { background-color: #000000;}
I believe that is stylevar doc_background unless it is custom. You have a custom style that has it's own classes that aren't vB classes. You may want to ask your designer what stylevars they intend you to use to change the pages.
The template for the article previews is also custom, which is probably why the images are not all the same size. You could add something like this to the additional.css template:
HTML Code:
.cms_article_txt_content img {
width: 200px;}