#302c2e should not be yellow - more like gray, rather dark tbh.
And it should be easily changeable, although it's always locked.
Can you tell me what browser you use? and maybe provide a screenshot?
Sure, browser is Firefox Desktop (whatever version is newest now), Chrome works fine, and as to the screenshot, here it is:
Damn, I've tried it out on Firefox on a Windows (10) machine and it works just fine. Not sure. Maybe a cache problem?
Can you try to run it with cache disabled (or incognito mode should also work just for testing it)?
If this is still a problem - maybe you'd be able to run it with dev-tools' console open and paste the errors that show up (if any)?
Incognito mode does nothing and console only gives itch.io relevant errors (like skipping unknown function 'monetization'. Embedded "game" code is not visible, so can't say if I've noiticed there something interesting or not (somethich that can point to the glitch in question).