Sorry, yes. I solved this part, another problem comes from some place else. The main-navigation ist set to top:86px, that works on desktop.
Was there actually another way without setting a margin-top to main-navigation to reach that the site-header and the main-navigation were just below each other and both sticky?
For mobile:
What should I change, so the site-header and main-navigation stay sticky and not under the mobile navigation when you scroll down?
Thanks, Erika