It’s possible by using the *script command to call the native background color switching functions. It involves *script though, so probably can’t be used in published games.
Example:
Hello
*fake_choice
#Black
*script changeBackgroundColor("black")
#Sepia
*script changeBackgroundColor("sepia")
#White
*script changeBackgroundColor("white")
World
NB: Color-switching doesn’t seem to work for me when testing in CSIDE, but does work when testing from the CS folder directly, or when testing in VSCode using the CS extension: New Choicescript extension for VS Code (2.0 now runs games!)
