Does anyone know how to make header fixed for the Pedro template?

Im using pedro template and would love to have our header with the primary nav to be fixed

@kamilrolda Add to Home > Design > Custom CSS

/* Desktop */
.Header {
   position: fixed !important;
   top: 0;
   left: 0;
   right: 0;
   z-index: 999;
}
/* Mobile */
.Mobile.loaded {
   position: fixed;
   top: 0;
   left: 0;
   right: 0;
   z-index: 999;
}

Reference: https://beaverhero.com/pedro-template-squarespace/#Sticky_Header