Problems with navigation menu

Hello, I have a problem with the search box and the navigation menu. Under Firefox both work without problems. With Chrome and Opera on the PC only the navigation, clicking on the search icon does not appear the search box. When I access the page with Chrome on mobile, the submenus in the menus do not work and also the search box does not appear. The website is: https://www.altenpflegeschueler.de. Can anyone help me fix this error?

kind regards

Marcell

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