Is it possible to change the colour of the menu text on top of the site as soon as you start scrolling?

Site URL: https://rabbit-bobcat-zbp2.squarespace.com

Password: edes
It's on squarespace 7.1

Hi all, help would be greatly appreciated: 

Am I overlooking this or do I need some code to achieve this: I would like the white menu text on top of all pages to turn into black as soon as you start scrolling down. If possible, then I would like the menu background bar to be white. (For now it's black because otherwise you can't read the menu)

It looks like you solved this?

.shrink {
    background: #fff !important
}

.shrink *:not(a.btn) {
    color: #000 !important
}

.shrink .header-nav-folder-item a {
    color: #fff !important
}