diff --git a/core/includes/theme.inc b/core/includes/theme.inc
index dfee854..656fc9c 100644
--- a/core/includes/theme.inc
+++ b/core/includes/theme.inc
@@ -1467,21 +1467,20 @@ function theme_get_suggestions($args, $base, $delimiter = '__') {
  *   An associative array containing:
  *   - content - An array of page content.
  *
  * @see system_page_attachments()
  */
 function template_preprocess_maintenance_page(&$variables) {
   // @todo Rename the templates to page--maintenance + page--install.
   template_preprocess_page($variables);
 
   // @see system_page_attachments()
-  $variables['#attached']['library'][] = 'core/normalize';
   $variables['#attached']['library'][] = 'system/maintenance';
 }
 
 /**
  * Prepares variables for install page templates.
  *
  * Default template: install-page.html.twig.
  *
  * @param array $variables
  *   An associative array containing:
diff --git a/core/modules/system/src/Tests/Theme/ThemeInfoTest.php b/core/modules/system/src/Tests/Theme/ThemeInfoTest.php
index aeb8846..ba191da 100644
--- a/core/modules/system/src/Tests/Theme/ThemeInfoTest.php
+++ b/core/modules/system/src/Tests/Theme/ThemeInfoTest.php
@@ -92,20 +92,20 @@ function testStylesheets() {
    * Tests that changes to the info file are picked up.
    */
   public function testChanges() {
     $this->themeHandler->install(array('test_theme'));
     $this->themeHandler->setDefault('test_theme');
     $this->themeManager->resetActiveTheme();
 
     $active_theme = $this->themeManager->getActiveTheme();
     // Make sure we are not testing the wrong theme.
     $this->assertEqual('test_theme', $active_theme->getName());
-    $this->assertEqual(['classy/base'], $active_theme->getLibraries());
+    $this->assertEqual(['classy/base', 'core/normalize'], $active_theme->getLibraries());
 
     // @see theme_test_system_info_alter()
     $this->state->set('theme_test.modify_info_files', TRUE);
     drupal_flush_all_caches();
     $active_theme = $this->themeManager->getActiveTheme();
-    $this->assertEqual(['classy/base', 'core/backbone'], $active_theme->getLibraries());
+    $this->assertEqual(['classy/base', 'core/normalize', 'core/backbone'], $active_theme->getLibraries());
   }
 
 }
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 88f9023..c8a8be5 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -514,21 +514,20 @@ function system_filetransfer_info() {
 }
 
 /**
  * Implements hook_page_attachments().
  *
  * @see template_preprocess_maintenance_page()
  * @see \Drupal\system\Controller\SystemController::setLinkActiveClass()
  */
 function system_page_attachments(array &$page) {
   // Ensure the same CSS is loaded in template_preprocess_maintenance_page().
-  $page['#attached']['library'][] = 'core/normalize';
   $page['#attached']['library'][] = 'system/base';
   if (\Drupal::service('router.admin_context')->isAdminRoute()) {
     $page['#attached']['library'][] = 'system/admin';
   }
 
   // Attach libraries used by this theme.
   $active_theme = \Drupal::theme()->getActiveTheme();
   foreach ($active_theme->getLibraries() as $library) {
     $page['#attached']['library'][] = $library;
   }
diff --git a/core/themes/classy/classy.info.yml b/core/themes/classy/classy.info.yml
index 93a5268..bd61ce0 100644
--- a/core/themes/classy/classy.info.yml
+++ b/core/themes/classy/classy.info.yml
@@ -1,9 +1,10 @@
 name: Classy
 type: theme
 description: 'A base theme with sensible default CSS classes added. Learn how to use Classy as a base theme in the <a href="https://www.drupal.org/theme-guide/8">Drupal 8 Theming Guide</a>.'
 package: Core
 version: VERSION
 core: 8.x
 
 libraries:
   - classy/base
+  - core/normalize