Keyboard viewer in macOS Mojave dark mode
Honestly, I don't know if they're supposed to, but they do, &amp; have done since the first beta. Still the same in the latest beta 10.14.2



Sorry, some confusion... the picture in the OP isn't the Accessibility keyboard, it's the "Show Keyboard Viewer" keyboard, which used to be white &amp; is now as above.

From High Sierra



The Accessibility keyboard seems to have been the same since High Sierra [can't test Sierra] &amp; didn't exist in El Capitan.