I have changed the default theme for Friendica.World.
It is still the 'Frio' theme but now with the 'Bookface' customisation, set to 'Auto Color Mode'.

The auto color mode means it switches between Light and Dark mode depending on your computer's setting.

If you want to change the theme and/or customisation, you can do so here: friendica.world/settings/displ…
You'll find the theme under 'General Theme Settings' and the customisation (Appearance) under 'Custom Theme Settings'