Reply To: Transparent Menu Below Header

[Tom]

That should work, then you can set it back to 1 when you hover:

.mobile-header-navigation.is_stuck:hover {
    opacity: 1;
}

Documentation: http://docs.generatepress.com/
Adding CSS: http://docs.generatepress.com/article/adding-css/
Ongoing Development: https://generatepress.com/ongoing-development