Thanks for writing in! To resolve your issue, please set the global background color first in the customizer or in X > Launch > Options > Layout & Design > Background Options. This setting will be the global background color.
To change the background color for your homepage, please add the following CSS code in the X > Launch > Theme Options > Global CSS (http://prntscr.com/evui3r) or in the customizer, Appearance > Customize > Custom > Edit GLOBAL CSS
background-color: white !important;
Only the homepage will have a white background using this code.
Please let us know how it goes.