// buffer to prevent positioning changes from happening right at edge of screen
  var buffer = 100;

  // initial window offset
  var prevScrollPosition = window.pageYOffset;

  // get Alert Bar height if present
  if($('#alertApp').length) {
    var alertBarHeight = $('#alertApp').outerHeight();
  } else {
    var alertBarHeight = 0;
  }

  // get WP Admin Bar height if present
  if($('#wpadminbar').length) {
    var wpAdminBarHeight = $('#wpadminbar').outerHeight();
  } else {
    var wpAdminBarHeight = 0;
  }

  // combined height of header + any ancillaries (alert bar, admin bar, etc)
  var headerHeight = $('header').outerHeight();
  var delta = headerHeight + alertBarHeight + wpAdminBarHeight;

  var initialHeaderOffset = alertBarHeight + wpAdminBarHeight;
  var distanceFromTop, firstScroll, headerTopOffset, scrollPosition;

  // determine if page is at top or lower down the page (i.e. refreshed) on page load
  if($(window).scrollTop() == 0) {
    firstScroll = true;
  } else {
    firstScroll = false;
  }


  $(window).scroll(function() {
    scrollPosition = $(this).scrollTop();

    // if scrolling up -> show menu
    if (prevScrollPosition > scrollPosition) {
      $('header').addClass("sticky-header").css({"top": headerTopOffset});
      var headerPosition = $('header').offset().top - $(this).scrollTop();
      if(headerPosition >= 0) {
        $('header').css({"position": "fixed", "top": 0});
        firstScroll = false;
        distanceFromTop = window.pageYOffset;
      }

      // if scrolling down from the top of the site, reposition header just above the
      // screen once user scrolls past it and any ancillaries (alert bar, admin bar, etc)
    } else if (firstScroll && scrollPosition > delta + buffer) {
      headerTopOffset = scrollPosition - (delta + buffer);
      $('header').css({"position": "absolute", "top": headerTopOffset});
      $('body').css({"padding-top": $('header').outerHeight()});
      firstScroll = false;

      // if scrolling down after header is sticky, change positioning to absolute so it scrolls off screen
      // - - - THE PROBLEM MAY BE HERE - - -
    } else if (!firstScroll) {
      $('header').css({"position": "absolute", "top": distanceFromTop});


      // once scrolled past the header, position it just above the window so it
      // scrolls back into view when you scroll up
      if(($('header').offset().top + headerHeight + buffer) < scrollPosition) {
        headerTopOffset = scrollPosition - (delta + buffer);
        $('header').removeClass("sticky-header");
      }
    }

    prevScrollPosition = scrollPosition;

    // if scrolled all the way to the top -> reset back to original positions
    if(scrollPosition <= initialHeaderOffset) {
      $('header').css({"position": "relative"}).removeClass("sticky-header");
      $('body').css({"padding-top": 0});
      firstScroll = true;
    }
  });