Blank space between hero area and content

Hi,

Silly CSS question I think: how can I get rid of the small band of white (blank) space between the hero areas of the various pages on this site and the content areas below them? (And also between the content at bottom + footer.) I’ve minimized the blank space for the moment by adding the following to Additional CSS:
.content {
margin-top: -5rem;
margin-bottom: -5rem;
}

But it’s inelegant and doesn’t totally get rid of the issue (but if I up it any more, then the titles of pages start to get cut off on mobile). I’d like a more elegant solution to let this theme know I just don’t want these random blank areas, but the theme is hard to customize in the free version and I’m not sure what option controls this (or why it’s there at all).

TIA!

The page I need help with: [log in to see the link]