This is a copy of this post to the official Discourse site.
On our Discourse hosted site (https://swi-prolog.discourse.group/) the Dark theme is no longer dark.
Notice in this clip from the hamburger menu that the theme Dark is selected yet the background is white
While on this site (https://meta.discourse.org/) from the hamburger menu that the theme Dark is selected yet the background is black.
I am only noting as a possible bug because I have no other evidence. If others can confirm or note that it is not happening for them it would be appreciated. 