Sticky header styling

I hope one day, sticky header styling will be integrated in the Customizer but for the time being there is a CSS solution:

/* Change sticky header background to white */
.main-navigation.navigation-clone {
    background-color: #FFF;

You might want to change the color of the text logo, menu nav links, mobile icon and mobile icon text:

.main-navigation.navigation-clone .navigation-branding a,
.main-navigation.navigation-clone .main-nav ul li a,
.main-navigation.navigation-clone {
	color: #000 !important;

Finally, you might want to reinstate the nav hover and nav currrent link color:

.main-navigation.navigation-clone .main-nav ul li a:hover, 
.main-navigation.navigation-clone .main-nav ul li.current-menu-item a {
	color: #ab2eba !important;