core/themes/seven/seven.info.yml | 15 +++++++++++++++
 core/themes/seven/seven.theme    | 18 ------------------
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/core/themes/seven/seven.info.yml b/core/themes/seven/seven.info.yml
index b983303..699c963 100644
--- a/core/themes/seven/seven.info.yml
+++ b/core/themes/seven/seven.info.yml
@@ -9,10 +9,25 @@ core: 8.x
 libraries:
  - seven/global-styling
 libraries-override:
+  core/drupal.vertical-tabs:
+    css:
+      component:
+        misc/vertical-tabs.css: false
+  core/jquery.ui:
+    css:
+      theme:
+        assets/vendor/jquery.ui/themes/base/theme.css: false
   core/jquery.ui.dialog:
     css:
       component:
         assets/vendor/jquery.ui/themes/base/dialog.css: false
+  classy/dialog:
+    seven/seven.drupal.dialog
+libraries-extend:
+  core/drupal.vertical-tabs:
+    - seven/vertical-tabs
+  core/jquery.ui:
+    - seven/seven.jquery.ui
 quickedit_stylesheets:
   - css/components/quickedit.css
 regions:
diff --git a/core/themes/seven/seven.theme b/core/themes/seven/seven.theme
index 4f7946c..29aaf62 100644
--- a/core/themes/seven/seven.theme
+++ b/core/themes/seven/seven.theme
@@ -187,21 +187,3 @@ function seven_form_node_form_alter(&$form, FormStateInterface $form_state) {
   $form['revision_information']['#type'] = 'container';
   $form['revision_information']['#group'] = 'meta';
 }
-
-/**
- * Implements hook_library_info_alter().
- */
-function seven_library_info_alter(&$libraries, $extension) {
-  if ($extension == 'core' && isset($libraries['drupal.vertical-tabs'])) {
-    unset($libraries['drupal.vertical-tabs']['css']['component']['misc/vertical-tabs.css']);
-    $libraries['drupal.vertical-tabs']['dependencies'][] = 'seven/vertical-tabs';
-  }
-  if ($extension == 'core' && isset($libraries['jquery.ui'])) {
-    unset($libraries['jquery.ui']['css']['theme']['assets/vendor/jquery.ui/themes/base/theme.css']);
-    $libraries['jquery.ui']['dependencies'][] = 'seven/seven.jquery.ui';
-  }
-  if ($extension == 'classy' && isset($libraries['dialog'])) {
-    unset($libraries['dialog']['css']['component']['css/components/dialog.css']);
-    $libraries['dialog']['dependencies'][] = 'seven/seven.drupal.dialog';
-  }
-}