Remove space under header image on mobile

Another thing please… I’ve tried what I could find in the forum to remove the gray area under the header but doesnt work for me. I know it says in the link below that its either i get a big header on mobile or i get responsive image but with big annoying space below. I’m hoping that maybe there’s now a compromise where I can have resized header image without the gray area below it.

https://ww.wp.xz.cn/support/topic/mobile-header-image-doesnt-resizeunresponsive/

Pls check my site on mobile: https://thewanderwalkers.com
Thanks

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