I had exactly the same problem. It was caused by very old version of PHP (5.4). After changing to 7.4 problem is gone.
1. Take a look at http://demos.cpothemes.com/brilliance/page-templates/wide-page/
it’s not full width, but limited to 1180.
2. I don’t have wide page layout in the page’s options, just with or without a sidebar.
btw. what’s the point of changing bg color when one can’t change fg?
I’m rising rate for good support 😉
