I have played around with the stylesheets and can not figure how to change the background color of the table that is outside of this table. I have included a screen shot to try and explain more.
That would be the body CSS tag usually unless that white area is something you programmed in which looks like it by the green color of the outer cell.
I have my default body set to the following code below but it still displays the white background. I am talking about the color within my circle that I have with the attached image in the first post. Not the green border around the whole page. Unless you think the color within the circle is a shade of green. If so I can assure you it is not. It might look that way because of the way I captured and had to shrink it.