hello Leo, good morning and thanks for responding so quickly!
For the static pages in the body I set in the css/editor different background-images and I use elementor only in the content.
All the general settings I made with the customizer/gp and it worked.
But in the single post part I can’t use elementor (doesn’t appear), I don’t know why, but it doesn’t matter, because I want to keep it simple. The client wants to write the single posts himself.
Now the problem is, that I can’t find an extra class to change only the content background in the single post page appart from the static pages.
Do you have any idea to solve it?