Change Color of menu background and fonts. Change size of the logo



I like the theme moesia very much. But i have two questions to make the theme more individual. How ca i change the color of the background ond the font in the “menu” On my website: when i go to “Der Verein” the background is white and the font is grey. I think it is not very easy to read this. how can i change the color there?

On the header Picture is the logo of our club. I think it is a little bit to small. How can I make it bigger?

Thank you for yout help!