   appendix = true;
    $(this).nextUntil($('h1, h2, h3')).addBack().appendTo($('d-appendix'));
  });

  // show d-appendix if we have appendix content
  $("d-appendix").css('display', appendix ? 'grid' : 'none');

  // localize layout chunks to just output
  $('.layout-chunk').each(function(i, val) {

    // capture layout
    var layout = $(this).attr('data-layout');

    // apply layout to markdown level block elements
    var elements = $(this).children().not('details, div.sourceCode, pre, script');
   