For some reason if I try to add color to my header it does show on mobile, but I got white background on desktop. I checked on multiple browsers.
Do you have any tips what causes this?
I disbled all plugins not connected to the theme.
The problem is caused by incorrect HTTP and HTTPS configuration: https://domain.com is the actual site URL, however, http://domain.com is used in Dashboard > Settings > General. In this case, it is necessary to configure URLs correctly.