By the way, does the name "Mac Classic" imply that this color scheme is somehow based on traditional Mac editors?
More or less, yes. The white background and the saturated blue keyword color, at least.
If so, do these editors also specify a light blue color for embedded source?
TextMate is the first Mac editor of any vintage capable of supporting embedded source, as far as I'm aware.
I'd be totally happy for someone to say "thou shalt use _this_ color for embedded source backgrounds in Mac Classic." I did intend to revisit that color, but haven't gotten back to it. Better suggestions always welcome.
Chris