Override deafult scroll handling for anchor links, set offset for sticky header.

x-pro-anchor-link-scroll.js

(function($) {

  $('a[href^="#"]:not(a[href="#"])').unbind('touchend click').on('touchend click', function(e) {
    var target = $(this.hash);

    if (target.length) {
      e.preventDefault();
      e.stopImmediatePropagation();
          
      var headerHeight = 50; // put your offset here in px
      $('html,body').animate({ scrollTop: target.offset().top - headerHeight }, 400);
    }

  });
})(jQuery);