Unfortunately, the CSS code did not help and Russian letters do not work. Below I gave an example with screenshots.
1. Создал метку в настройках. В её названии русская буква “К”
1 screen
2. Chose the color and logo
2 screen
3. I put a new placemark on the map and clicked ” save”
3 screen
4. After saving, the placemark’s color and logo disappear
4 screen
If you remove the Russian letters “K”, “P”, “N” from the name, everything works perfectly. I learned how to replace these letters in placemarks with English ones so that the placemark works properly. But the CSS code didn’t help speed up map loading. The page still loads for 13-15 seconds. I’ve tried various plugins, but they don’t help with this issue. I temporarily had to disable the card and replace it with Yandex maps because people complain that it doesn’t work. They can’t wait for the map to load and leave the site. You can try downloading it yourself. I attach a link to my site
Каменские известия