core/modules/block/block.module                    |  1 -
 core/modules/block/src/Tests/BlockHtmlTest.php     |  2 +-
 .../system/src/Tests/Menu/BreadcrumbTest.php       |  2 +-
 core/modules/system/system.module                  |  2 ++
 .../templates/block--system-menu-block.html.twig   | 34 ++++++++++++++++++----
 .../views/src/Tests/Plugin/DisplayPageWebTest.php  |  4 +--
 core/themes/bartik/css/style.css                   |  7 ++---
 .../templates/block--system-menu-block.html.twig   |  2 +-
 8 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/core/modules/block/block.module b/core/modules/block/block.module
index 9582874..339d163 100644
--- a/core/modules/block/block.module
+++ b/core/modules/block/block.module
@@ -267,7 +267,6 @@ function template_preprocess_block(&$variables) {
   $variables['base_plugin_id'] = $variables['elements']['#base_plugin_id'];
   $variables['derivative_plugin_id'] = $variables['elements']['#derivative_plugin_id'];
   $variables['label'] = !empty($variables['configuration']['label_display']) ? $variables['configuration']['label'] : '';
-  $variables['label_display'] = $variables['configuration']['label_display'];
   $variables['content'] = $variables['elements']['content'];
   // A block's label is configuration: it is static. Allow dynamic labels to be
   // set in the render array.
diff --git a/core/modules/block/src/Tests/BlockHtmlTest.php b/core/modules/block/src/Tests/BlockHtmlTest.php
index b6cb078..955955a 100644
--- a/core/modules/block/src/Tests/BlockHtmlTest.php
+++ b/core/modules/block/src/Tests/BlockHtmlTest.php
@@ -48,7 +48,7 @@ function testHtml() {
     $this->assertFieldByXPath('//div[@id="block-test-html-block" and @data-custom-attribute="foo"]', NULL, 'HTML ID and attributes for test block are valid and on the same DOM element.');
 
     // Ensure expected markup for a menu block.
-    $elements = $this->xpath('//div[contains(@class, :div-class)]/div/ul[contains(@class, :ul-class)]/li', array(':div-class' => 'block-system', ':ul-class' => 'menu'));
+    $elements = $this->xpath('//nav[contains(@class, :nav-class)]/div/ul[contains(@class, :ul-class)]/li', array(':nav-class' => 'block-menu', ':ul-class' => 'menu'));
     $this->assertTrue(!empty($elements), 'The proper block markup was found.');
   }
 
diff --git a/core/modules/system/src/Tests/Menu/BreadcrumbTest.php b/core/modules/system/src/Tests/Menu/BreadcrumbTest.php
index ea55662..cf5ab1a 100644
--- a/core/modules/system/src/Tests/Menu/BreadcrumbTest.php
+++ b/core/modules/system/src/Tests/Menu/BreadcrumbTest.php
@@ -278,7 +278,7 @@ function testBreadCrumbs() {
       // untranslated menu links automatically generated from menu router items
       // ('taxonomy/term/%') should never be translated and appear in any menu
       // other than the breadcrumb trail.
-      $elements = $this->xpath('//div[@id=:menu]/descendant::a[@href=:href]', array(
+      $elements = $this->xpath('//nav[@id=:menu]/descendant::a[@href=:href]', array(
         ':menu' => 'block-bartik-tools',
         ':href' => url($link_path),
       ));
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 6142dfc..f6d1418 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -157,10 +157,12 @@ function system_theme() {
     // themes. We explicitly define theme suggestions here so that the block
     // templates in core/modules/system/templates are picked up.
     'block__system_branding_block' => array(
+      'render element' => 'elements',
       'base hook' => 'block',
       'template' => 'block--system-branding-block',
     ),
     'block__system_menu_block' => array(
+      'render element' => 'elements',
       'base hook' => 'block',
       'template' => 'block--system-menu-block',
     ),
diff --git a/core/modules/system/templates/block--system-menu-block.html.twig b/core/modules/system/templates/block--system-menu-block.html.twig
index acadc15..6c0fbe6 100644
--- a/core/modules/system/templates/block--system-menu-block.html.twig
+++ b/core/modules/system/templates/block--system-menu-block.html.twig
@@ -4,7 +4,29 @@
  * Default theme implementation for a menu block.
  *
  * Available variables:
- * - …
+ * - plugin_id: The ID of the block implementation.
+ * - label: The configured label of the block if visible.
+ * - configuration: A list of the block's configuration values.
+ *   - label: The configured label for the block.
+ *   - label_display: The display settings for the label.
+ *   - module: The module that provided this block plugin.
+ *   - cache: The cache settings.
+ *   - Block plugin specific settings will also be stored here.
+ * - block - The full block entity.
+ *   - label_hidden: The hidden block title value if the block was
+ *     configured to hide the title ('label' is empty in this case).
+ *   - module: The module that generated the block.
+ *   - delta: An ID for the block, unique within each module.
+ *   - region: The block region embedding the current block.
+ * - content: The content of this block.
+ * - attributes: HTML attributes for the containing element.
+ *   - id: A valid HTML ID and guaranteed unique.
+ * - title_attributes: HTML attributes for the title element.
+ * - content_attributes: HTML attributes for the content element.
+ * - title_prefix: Additional output populated by modules, intended to be
+ *   displayed in front of the main title tag that appears in the template.
+ * - title_suffix: Additional output populated by modules, intended to be
+ *   displayed after the main title tag that appears in the template.
  *
  * Headings should be used on navigation menus that consistently appears on
  * multiple pages. When this menu block's label is configured to not be
@@ -27,22 +49,22 @@
 %}
 {% set heading_id = attributes.id ~ '-menu'|clean_id %}
 <nav{{ attributes.addClass(classes) }} role="navigation" aria-labelledby="{{ heading_id }}">
-  {# Block title. If not displayed, we still provide it for screen readers. #}
-  {% if not label_display %}
+  {# Label. If not displayed, we still provide it for screen readers. #}
+  {% if not configuration.label_display %}
     {% set title_attributes = title_attributes.addClass(['visually-hidden']) %}
   {% endif %}
   {{ title_prefix }}
     <h2 id="{{ heading_id }}"{{ title_attributes }}>{{ configuration.label }}</h2>
   {{ title_suffix }}
 
-  {# Menu #}
-  {% if label_display %}
+  {# Menu. If no label is displayed, don't wrap it in <div class="content">. #}
+  {% if configuration.label_display %}
     <div{{ content_attributes.addClass('content') }}>
   {% endif %}
     {% block content %}
       {{ content }}
     {% endblock %}
-  {% if label_display %}
+  {% if configuration.label_display %}
     </div>
   {% endif %}
 </nav>
diff --git a/core/modules/views/src/Tests/Plugin/DisplayPageWebTest.php b/core/modules/views/src/Tests/Plugin/DisplayPageWebTest.php
index 3750601..d975a80 100644
--- a/core/modules/views/src/Tests/Plugin/DisplayPageWebTest.php
+++ b/core/modules/views/src/Tests/Plugin/DisplayPageWebTest.php
@@ -108,7 +108,7 @@ public function testPageDisplayMenu() {
     $this->drupalPlaceBlock('system_menu_block:tools');
     $this->drupalGet('<front>');
 
-    $menu_link = $this->cssSelect('div.block-menu ul.menu a');
+    $menu_link = $this->cssSelect('nav.block-menu ul.menu a');
     $this->assertEqual((string) $menu_link[0], 'Test menu link');
 
     // Update the menu link.
@@ -117,7 +117,7 @@ public function testPageDisplayMenu() {
     ], t('Save'));
 
     $this->drupalGet('<front>');
-    $menu_link = $this->cssSelect('div.block-menu ul.menu a');
+    $menu_link = $this->cssSelect('nav.block-menu ul.menu a');
     $this->assertEqual((string) $menu_link[0], 'New title');
   }
 
diff --git a/core/themes/bartik/css/style.css b/core/themes/bartik/css/style.css
index 29ecdc4..9a7ad23 100644
--- a/core/themes/bartik/css/style.css
+++ b/core/themes/bartik/css/style.css
@@ -652,10 +652,9 @@ body:not(:target) #header .block-menu:first-child .menu-toggle-target-show:targe
 
 /* --------------- Secondary Menu ------------ */
 #header .block-menu:nth-child(2) {
-    border: 1px solid red;
-    position: absolute;
-    top: 0;
-    right: 0; /* LTR */
+  position: absolute;
+  top: 0;
+  right: 0; /* LTR */
 }
 [dir="rtl"] #header .block-menu:nth-child(2) {
   right: inherit;
diff --git a/core/themes/bartik/templates/block--system-menu-block.html.twig b/core/themes/bartik/templates/block--system-menu-block.html.twig
index 1e81581..b6c0412 100644
--- a/core/themes/bartik/templates/block--system-menu-block.html.twig
+++ b/core/themes/bartik/templates/block--system-menu-block.html.twig
@@ -12,7 +12,7 @@
 {% set hide_anchor = "hide-" ~ attributes.id|clean_id %}
 {% block content %}
   {# When rendering a menu without label, render a menu toggle. #}
-  {% if not label_display %}
+  {% if not configuration.label_display %}
     <div class="menu-toggle-target menu-toggle-target-show" id="{{ show_anchor }}"></div>
     <div class="menu-toggle-target" id="{{ hide_anchor }}"></div>
     <a class="menu-toggle" href="#{{ show_anchor }}">{{ 'Menu'|t }}</a>