Ismael,
I will be happy to provide screen shots – see below. The first one is the style tab of the enfold child theme. As you can see I have it set to be a boxed layout with a green color for the background. Even the preview above the settings shows this to be the background. The second screenshot shows the site’s homepage. I have not been able to change the blue background. I have not added anything in the Quick CSS to modify the background. I have also cleared the cache just in case.

http://www.msfwebdesign.com/msf_redo/wp-content/uploads/2014/02/style-tab.tiff

http://www.msfwebdesign.com/msf_redo/wp-content/uploads/2014/02/homepage-with-blue.tiff