Mobile Headline spacing

Hii there!

I am working on this site: https://kelsey-boylan.squarespace.com/

And for mobile, I would love to be able to reduce the spacing between the headlines on the homepage – is there a way to override the text block box spaces?

also, still on mobile, my client asked to remove the navigation bar for the homepage, how can I reduce the white space on the header for just mobile?

thank you so much!