Header : remove white space

Hello !

My page is here : https://www.decroux.ch/

Very small, but I expect to developp the site in a second time. Anyway, as you can see, there’s too much white spaces above and under the logo. How can I reduce this? (actually, I dont need any menu…).

Second question, how can I hide the page title?

Thanks a lot for your help…

Marc