Stop logo minimising on scroll

Hi,

Im really enjoying the flexibility of this theme.

One thing I cant figure out is how to stop my logo from resizing on scroll. Ive tried adding custom css and setting height at 100% for any element I think is relevant but no matter what I do it still shrinks a little bit on scroll.

Is it possible to keep the logo the same size in the fixed header when scrolling using css?

Thanks,
Emily