Resizing homepage banner for mobile

Site URL: https://www.clemerizzo.com/

Hi!

I am trying to resize my homepage banner for mobile to reflect my homepage on desktop but I can't find a code that will work. Currently, the mobile banner has too much white space on top and bottom and is cropped in too far. 

Thanks so much in advance for any help!

Add to Home > Design > custom CSS

@media screen and (max-width:767px) {
.homepage #page section:first-child {
    margin-top: 0;
}
}