Nav bar menu items scrolling so header stays fixed

Hi

I’m using the suffusion theme and for the life of me I cant figure out a few things. I’ve searched everywhere and found nothing (or at least nothing that I could understand)

URL – https://www.mile27.com.au

problems –
1. why does my logo have the white fuzzy bits around it – it doesnt on the gif file that I uploaded?
2. How to I move the page menues in the nav bar so I can have the logo on the left and the nav bar menues either centred or on the right
3. How can i make the post scroll down but the logo and header and nav bar remain at the top

Help greatly appreciated.