[cannam]

Oh yes, I see there's a theme entry down in the Customize Emacs submenu at the bottom of the Options menu. Logical though that may be, I had no idea.

It's not as if I even have a complicated custom theme in my .emacs - I have a couple of lines, but mainly I just don't change the colours from their defaults any more. I care a great deal about what my editor looks like, but it turns out that the default colours - black text, white background, pleasantly dark font-lock colours - are perfect for me already. (I waste my time on fonts instead)