Main Menu color changes when scrolling

Hi,

on my front page i have a white menu with a transparent backround. It not sticky !

I’ve used this code to keep it transparent when scrolling

.home .header_bg {
background: transparent;
}

On my other pages i have a black menu with a white backround which is fine.
When I start scrolling on my front page, the white menu changes to black.
How can I keep it white when scrolling ?? It not sticky !

Henning