Help with this theme

Hi.
I hope somebody can help me.
The creator of the theme is not available, his website is under construction.
The theme is exactly what I need, unfortunately there are some bugs that I can’t fix or change.

1. The colors under the posts (red/blue). Can they only be changed in the css?
2. If you go to a post, the headline is directly on the logo.
   Where can I change that?
3. The number of posts on the start page cannot be changed, but I can’t find anything there either. Maybe someone has a tip for me.
   See everything at:
   https://eiszeit-in-kassel.de

Thank you for your help.

Regards
Webbs

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