The pendulum has swung (I have swung the pendulum) hard in favor of “this is an interpreter option” rather than “this is a game option”.
Quixe leaves the color entirely up to the page’s CSS file. Therefore, Lectrote is able to provide a universal “color theme” preference by controlling the CSS on the page. The game can’t override that, in Lectrote.
You gave me enough clues to let me do that for my game (links on the sidebar for “dark theme” and “light theme” which use Javascript to swap stylesheets) – thank you.
Though I’ll mark your comment as the solution as an incentive
I have a feeling that this would work at the text-level but woudn’t be able to change the screen background/text colours more generally. Is that right?
Not at all. You could create channel data to notify the UI of any change you want. That’s the fundamental point of channel IO over glk. You have complete control over the client and it’s look and feel. I’ll whip an addition to the cloak example.
Well, just as an option as a starter or an exemplar or alternative, in addition to Andrew’s point, you can blag the control panel I developed for Worldsmith to customise CSS in game window.
You can see what I ended up with in the online version of Daddy’s Birthday on Itch. There are just two links – “Dark theme” for the default of white-on-black, and “Light theme” to change to black-on-white.