How can I use code to change drop down item on header?

When I scroll down, the drop-down item of ''camps'' goes completely black.

I would like that is white text and black background instead of all black when I scroll. Just like it is when I don't scroll.

My website is www.coastlinejj.com

Thank you!

You can use this to Website > Website Tools > Custom CSS

header#header.shrink span.header-nav-folder-item-content {
    color: white !important;
}