change cookie style

How can I change the style here? I would like to: 1. Change this text to German. 2. Change the appearance here so that it looks like 3 (black background, white text).

4. I would like the header on the homepage to be invisible and only appear when scrolling in the mobile view. And it should also be like this in the desktop view – currently, the header doesn’t appear at all when scrolling (desktop view).

Thanks, Alex