Adjust colours and keep them after a update?

"How can you adjust the colors in the submenu when submitting a new event? We had done this before but don't remember exactly how. After the update, they were reset, and now 'General' and 'Description' appear in orange."
Thx in Advance!

Thanks for giving more specified infos, screenshots etc.

The Colours in this Menue

you use the old legacy style, so you need to change jem.css. when I look into it it says me jem.css line 626

Thank you very much!!!

Is there any way to ensure that this file retains its settings after a future update?