Until very recently the "site chooser" dropdown looked the same everywhere for me, approximately like this:
Just now I went to a meta site and saw weird meta-themed colors:
Holy orange links, Batman! That's new.
So I looked at some other sites, and even on main the chooser sometimes has varied colors seemingly derived from the site theme:
I tested in an incognito window (and not logged in) -- same styling. Firefox.
After posting this (originally just about the site chooser) I discovered that the problem occurs with the global inbox, moderator diamond inbox, and achievements dropdowns too. Here's the last of those:
(I can't show you either inbox right now without doctoring because privacy, but you get the idea I hope.)
Could we please have a return to consistency? I think this is unintended, right?