EDIT: finally got it to work after creating the page again. Is there a possibility to have an active menu item (the page you’re currently on) to have a different color in the menu?
No that didn’t help. It seems that the page “reparatie” seems to ignore the settings.
I did set a custom CSS which should make the menu gray instead of transparent (just like on the other pages except home), but it doesn’t work and keeps being transparent.
The menu should have the same gray color when you scroll down and it gets sticky.
And yes, the gray colors are set at Customize > Colors > Header.
To me it starts to look like the theme is broken: ignoring settings doesn’t seem good to me. I just want to get the 'reparatie" page the same as every other page (except home). Why can all the pages be that way but doesn’t the reparatie page want to cooperate?