Altering CSS for header

I recently switched over to wordpress for my site. A friend of mine changed the navigation menus to highlight when hovered over at my request. First, when I hover over HOME isn’t centered properly but all the others are. Second, I would like to hover background colour to remain while the person views the page…just like here on WP. Is there a way to do that?

Here’s my site but without the changes if you need to see it. https://footprintsmusic.ca

Thanks!