Sticky header for mobile works in customizer not on the web

This code for sticky header for mobile works in Customizer, but not on the web: see: https://temp.hotelonsepen.nl/

/* sticky header on smartphone */

@media only screen and (max-width: 767px) {
.responsive #top #main !important {
/* Margin top value should be equal to header height*/
margin-top: 150px !important;
}
.responsive #top #wrap_all #header {
position: fixed !important;
}
}

What is wrong?

Grtz. Fred