diff --git a/core/misc/collapse.js b/core/misc/collapse.js
index f635647..9065473 100644
--- a/core/misc/collapse.js
+++ b/core/misc/collapse.js
@@ -12,11 +12,18 @@
    *
    * @constructor Drupal.CollapsibleDetails
    *
-   * @param {HTMLElement} node
+   * @param {HTMLDetailsElement} node
+   *   The `<details>` tag to process.
    */
   function CollapsibleDetails(node) {
     this.$node = $(node);
-    this.$node.data('details', this);
+    // Details tag polyfill.
+    if (!Modernizr.details) {
+      this.$node.addClass('collapse-processed');
+      // Initialize and setup the legend, replicate summary tag functionality.
+      this.setupLegend();
+    }
+
     // Expand details if there are errors inside, or if it contains an
     // element that is targeted by the URI fragment identifier.
     var anchor = location.hash && location.hash !== '#' ? ', ' + location.hash : '';
@@ -25,8 +32,7 @@
     }
     // Initialize and setup the summary,
     this.setupSummary();
-    // Initialize and setup the legend.
-    this.setupLegend();
+
   }
 
   $.extend(CollapsibleDetails, /** @lends Drupal.CollapsibleDetails */{
@@ -50,12 +56,24 @@
      */
     setupSummary: function () {
       this.$summary = $('<span class="summary"></span>');
+
+      this.$node.find('> summary')
+        .append(this.$summary);
+
       this.$node
-        .on('summaryUpdated', $.proxy(this.onSummaryUpdated, this))
+        .on('summaryUpdated', this.onSummaryUpdated.bind(this))
         .trigger('summaryUpdated');
     },
 
     /**
+    * Update summary.
+    */
+    onSummaryUpdated: function () {
+      var text = $.trim(this.$node.drupalGetSummary());
+      this.$summary.html(text ? ' (' + text + ')' : '');
+    },
+
+    /**
      * Initialize and setup legend markup.
      */
     setupLegend: function () {
@@ -73,15 +91,14 @@
         .prepend($legend.contents())
         .appendTo($legend);
 
-      $legend
-        .append(this.$summary)
-        .on('click', $.proxy(this.onLegendClick, this));
+      $legend.on('click', this.onLegendClick.bind(this));
     },
 
     /**
      * Handle legend clicks.
      *
      * @param {jQuery.Event} e
+     * jQuery Event object.
      */
     onLegendClick: function (e) {
       this.toggle();
@@ -89,15 +106,7 @@
     },
 
     /**
-     * Update summary.
-     */
-    onSummaryUpdated: function () {
-      var text = $.trim(this.$node.drupalGetSummary());
-      this.$summary.html(text ? ' (' + text + ')' : '');
-    },
-
-    /**
-     * Toggle the visibility of a details element using smooth animations.
+     * Toggle the value of the open attribute.
      */
     toggle: function () {
       var isOpen = !!this.$node.attr('open');
@@ -123,10 +132,7 @@
    */
   Drupal.behaviors.collapse = {
     attach: function (context) {
-      if (Modernizr.details) {
-        return;
-      }
-      var $collapsibleDetails = $(context).find('details').once('collapse').addClass('collapse-processed');
+      var $collapsibleDetails = $(context).find('details').once('collapse');
       if ($collapsibleDetails.length) {
         for (var i = 0; i < $collapsibleDetails.length; i++) {
           CollapsibleDetails.instances.push(new CollapsibleDetails($collapsibleDetails[i]));
diff --git a/core/modules/comment/comment-entity-form.js b/core/modules/comment/comment-entity-form.js
index 3ad1a3d..22cda4a 100644
--- a/core/modules/comment/comment-entity-form.js
+++ b/core/modules/comment/comment-entity-form.js
@@ -14,8 +14,8 @@
   Drupal.behaviors.commentFieldsetSummaries = {
     attach: function (context) {
       var $context = $(context);
-      $context.find('fieldset.comment-entity-settings-form').drupalSetSummary(function (context) {
-        return Drupal.checkPlain($(context).find('.js-form-item-comment input:checked').next('label').text());
+      $context.find('.comment-node-settings-form').drupalSetSummary(function (context) {
+        return Drupal.checkPlain($(context).find('.js-form-item-comment-0-status input:checked').next('label').text());
       });
     }
   };
diff --git a/core/themes/classy/css/components/collapse-processed.css b/core/themes/classy/css/components/collapse-processed.css
index 3ed2e35..4367da3 100644
--- a/core/themes/classy/css/components/collapse-processed.css
+++ b/core/themes/classy/css/components/collapse-processed.css
@@ -30,3 +30,6 @@
   -webkit-transform: rotate(90deg);
   transform: rotate(90deg);
 }
+.collapse-processed .details-title {
+  color: #333;
+}
diff --git a/core/themes/seven/css/components/entity-meta.css b/core/themes/seven/css/components/entity-meta.css
index 9877ec3..8ed3c02 100644
--- a/core/themes/seven/css/components/entity-meta.css
+++ b/core/themes/seven/css/components/entity-meta.css
@@ -55,5 +55,7 @@
   text-shadow: 0 1px 0 white;
 }
 .entity-meta details .summary {
- display: none; /* Hide JS summaries. @todo Rethink summaries. */
+  color: #666;
+  text-transform: none;
+  font-size: 0.85em;
 }