I have tried through 'customize theme' but the left and right edges of the screen (background?) remain white no matter what. I've used file manager in my cpanel to directly edit the main.css bakground color but to no effect. I'm trying to get users to focus on my page by removing the whitespace around it and leaving a crisp white page on the screen. The color I want to use is dark grey although an image might also be an option (e.g. graduated grey.jpg)