Header

We have a problem in the website header.

In the customizer is activated:
“Hold header up when the site visitor is scrolling”.
This does not work on our site.

On the smartphone, the preview does not open when you click on the menu.

These two issues do not occur when the program is opened in edit mode on the desktop at the same time. When scrolling, the headers header does not display the background color of the header but only the background color of the page.

The input in the Customizer “Additional CSS” is:

# site-header {background-color: #DECBAE; }

Can someone help us here with the problem solving?

Best regards from the Flachshof

The page I need help with: [log in to see the link]