It is nothing ;-)

Thanks a lot nice one.

Thanks, I really appreciate it.

Thanks ever so much.

Thank you. I have updated the colors a bit but the rendering remains as it used to be. It's pleasant and doesn't disturb the view too much.

My pleasure. I myself use this theme on the laptop because I have a small screen 1368x766) and it looks good on it. On larger screens I don't know if it renders best.

Separators...
I couldn't do anything about those, because some older themes I couldn't make with the advanced editor that exists today. Currently I can change the colors of all Firefox elements, even the separators in the drop-down menus. The problem is remembering to do it because there are a lot of values to change that then you can't figure out.

I am very grateful to you.

I understand the problem! I will try to mitigate it.
As well as in the theme Senzune.
Geek and Senzune are the oldest themes I have done. In those years there were not many interaction options in the GUI of the skin editor in firefox.