How can I change header background color in Burke template, Brine Family

Can't seem to find it anywhere. Perhaps CSS needed?

@ripatrip Add to Home > Design > Custom CSS

.Header.Header--bottom {
   background: #f1f2f3;
}
.Mobile-bar {
   background: #f1f2f3;
}

Reference: https://beaverhero.com/burke-squarespace/#HeaderBackgroundColor