Dark Mode in Toad12.6

Is it possible to enable Dark Mode for the whole application?

No, but it's on our radar, development-wise.

The closest you can come now is adjusting editor and grid colorization in options.

Hej John,
have you already implemented it?

Dark mode will be in the next release, 15.1, which is due out in mid-late January.

If you upgrade to 15.0 now, then you can also install the beta and try it out in beta.