Live site on the top (beta7+53), test site on the bottom (beta9+25).
Top has some prettiness and auto-completion (e.g. typing a { then hitting enter slaps in a }), bottom is just plain text. The customization themselves are applying and working fine, though.
I removed any extra plugins from the test site and did a rebuild before posting here in case that was an issue. I just noticed though I accidentally left one in (identical to one of the plugin howtos for putting something in the hamburger menu), I’ll take that one out and try again (will have to be later in the day unfortunately) if the issue is only showing up on my site.