Hi,
To achieve that, you can add this under Custom > Edit Global Javascript in the Customizer.
jQuery(document).ready(function($){
$(window).scroll(function(){
var $logobar= $('.x-logobar').offset().top - $('#wpadminbar').outerHeight();
if ( $(this).scrollTop() >= $logobar ) {
$('.x-logobar').addClass('x-logobar-fixed-top');
} else {
$('.x-logobar').removeClass('x-logobar-fixed-top');
}
})
});
Then add this in Edit Global CSS
.x-logobar-fixed-top {
position:fixed;
width:100%;
top:0;
z-index:99999;
}
.x-navbar.x-navbar-fixed-top {
top:106px;
}
Hope that helps.