Background Change

Hey people!

I am using the them “Suffusion” for my WordPress site: http://www.evony4noobs.com. I only started using Suffusion yesterday and I absolutely love it. However, one problem I ran into today was how to change the background. Right now, it is just a dull dark grey background and I would like to change that with a custom background I have made.

Since Suffusion is such a highly customizable theme, there is probably an option to change it. However, I have not yet found that, so if anyone could please teach or show me how to do that, I would really appreciate it. If CSS code editing is needed to perform this task, could someone please tell me what I should change and into what.

Thanks in advance!