Landing Page - NAVBAR - help

Hi guys, how are you? First of all sorry for my bad english. I’m trying to improving it (advices are always welcome!!).

I’m coding my first land page and I’ve few problems with the navbar. I’m working on this link:

With @media I’d like to center my immage with the rest of the nav elements. I tried different solutions I found on the web, but none of them worked.

I’d like to put the button one over the other too.

How can I do? What I’m doing wrong?