I’ve run into this issue a few times and tried to ignore it because I figured it was a nitpicky thing that only likely bothers me and maybe I’d get used to it, but not so much.
MDN has an established set of style rules. We’ve used them for many years now, and they seem to generally serve us well.
Given that the interactive examples are embedded into MDN, I feel pretty strongly that they should be following MDN’s style rules, rather than some other project’s style rules. Not doing so creates incongruities and variations in our content that can confuse contributors, make translations more complicated, and potentially make content more difficult to follow for certain readers.
Why aren’t we using MDN’s style rules for interactive examples? I think this is a real problem that needs to be discussed. We spend a good bit of time trying to manage content to follow our style rules as it is, without intentionally introducing stuff that deviates from them.