White Space on mobile

Site URL: https://www.x70.co.uk/

Hi

I am putting together a website and I am struggling with white space top and bottom of either a photo or a slide gallery on my homepage for mobile.

Any ideas? 

I have tried code from other posts and I have had no luck 

Hi. It looks like you solved with this code?

@media screen and (max-width: 767px) {
    .homepage .gallery-slideshow {
        margin-bottom:0 !important;
        height: 40vh !important
    }
}