Removing White Space Under Navigation Bar Responsively

Hello- I have run into a roadblock re-designing my website pages with the Nirvana theme, using the Elementor page builder. I get the dreaded white space between the hero image and the menu bar and while the negative margin for the hero section works on the desktop, it ends up covering up the menu on the mobile version. I can’t see any reason this is happening from a theme perspective (content padding is set to 0) but I can get the hero image flush without negative margins on other themes. Interestingly, on the pages without a negative margin, if you make the window smaller, the hero image becomes flush with the menu as desired. I’ve scoured the web and am desperate for some help here. Thank you way in advance!

For reference, here is a page that has the white space problem but shows fine on mobile: http://yacancerconnection.org/our-mission/

Here is a page that has a negative margin and shows fine on a desktop but covers the menu on mobile: http://yacancerconnection.org/meet-our-founders/

Website: www.yacancerconnection.org