June 2022
Try writing some code along the lines of
body { background-color: #000000 !important; }
The snippet should force, as long as EA's team hasn't set the background colour anywhere else using the !important tag, the background colour to black, if you want another colour then change the #000000 to a HEXIDECIMAL colour of your choice. The code is case and spelling sensitive so copy it with the same spellings and capitalization
January 2023
But why? Origin should have this option by now without our forcing the app to comply with not blinding us by our writing any sort of code. Not blaming you for the suggestion, just questioning why we, the end users, must learn to do this.