     var toggleTests = function(heading) { toggle(heading.parentNode.children[1]);};
      var toggleDetails = function(detailClass) {
        var details = document.querySelectorAll('.' + detailClass);
        for (var i = details.length - 1; i >= 0; i--) { toggle(details[i]);};
      };
      var hideAll = function(collection) {
        for (var i = collection.length - 1; i >= 0; i--) { hide(collection[i]); };
      }
      var showAll = function(collection) {
        for (var i = collection.length - 1; i