The old black theme is available in https://forum.cuberite.org/usercp.php?action=options if anyone wants to continue using it.
EDIT by NiLSPACE:
See 'Board Style' in the 'Other Options' panel on the bottom right of the screen.
EDIT by NiLSPACE:
See 'Board Style' in the 'Other Options' panel on the bottom right of the screen.