I added the code to mystypes.css . There one already there is for PLAC, that you gave me. It works fine now in Colours; not in webtrees; not in Xenea; okay in kiwitrees.
In Firefox, all themes work.
----- [updated: 31Dec2022] MacOS: 10.15.7 (Catalina) Safari 14.1.2; Firefox 108.0.1 (64-bit); 108.0.1462.54 (Official build) (x86_64)
Alter-Drukarsh connections | The Garelick: 3.3.11b - PHP 8.0 FastCGI - mySQL 8.