diff --git a/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php b/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
index d744e19..a8904e6 100644
--- a/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
+++ b/core/lib/Drupal/Core/Render/BareHtmlPageRenderer.php
@@ -74,10 +74,6 @@ protected function renderBarePage(array $content, $title, array $page_additions,
     // information about this; the exact same pattern is used there and
     // explained in detail there.
     drupal_render_root($html['page']);
-
-    // Add the bare minimum of attachments from the system module and the
-    // current maintenance theme.
-    system_page_attachments($html['page']);
     return drupal_render($html);
   }
 
diff --git a/core/themes/seven/seven.info.yml b/core/themes/seven/seven.info.yml
index 1277db9..ced18ef 100644
--- a/core/themes/seven/seven.info.yml
+++ b/core/themes/seven/seven.info.yml
@@ -7,39 +7,8 @@ tags: 'multi-column, fluid, responsive, sans-serif, accessible'
 package: Core
 version: VERSION
 core: 8.x
-stylesheets:
-  screen:
-    - css/base/elements.css
-    - css/base/typography.css
-    - css/components/admin-list.css
-    - css/components/admin-options.css
-    - css/components/admin-panel.css
-    - css/components/block-recent-content.css
-    - css/components/content-header.css
-    - css/components/breadcrumb.css
-    - css/components/buttons.css
-    - css/components/buttons.theme.css
-    - css/components/comments.css
-    - css/components/messages.css
-    - css/components/dropbutton.component.css
-    - css/components/entity-meta.css
-    - css/components/field-ui.css
-    - css/components/form.css
-    - css/components/help.css
-    - css/components/menus-and-lists.css
-    - css/components/modules-page.css
-    - css/components/node.css
-    - css/components/page-title.css
-    - css/components/pager.css
-    - css/components/skip-link.css
-    - css/components/tables.css
-    - css/components/tabs.css
-    - css/components/tour.theme.css
-    - css/components/update-status.css
-    - css/components/views-ui.css
-    - css/layout/layout.css
-    - css/layout/node-add.css
-    - css/theme/appearance-page.css
+libraries:
+  - seven/base
 stylesheets-override:
   - css/components/vertical-tabs.css
   - css/components/jquery.ui.theme.css
diff --git a/core/themes/seven/seven.libraries.yml b/core/themes/seven/seven.libraries.yml
index a794871..ae31ba4 100644
--- a/core/themes/seven/seven.libraries.yml
+++ b/core/themes/seven/seven.libraries.yml
@@ -1,3 +1,39 @@
+base:
+  version: VERSION
+  css:
+    theme:
+      css/base/elements.css: { media: screen }
+      css/base/typography.css: { media: screen }
+      css/components/admin-list.css: { media: screen }
+      css/components/admin-options.css: { media: screen }
+      css/components/admin-panel.css: { media: screen }
+      css/components/block-recent-content.css: { media: screen }
+      css/components/content-header.css: { media: screen }
+      css/components/breadcrumb.css: { media: screen }
+      css/components/buttons.css: { media: screen }
+      css/components/buttons.theme.css: { media: screen }
+      css/components/comments.css: { media: screen }
+      css/components/messages.css: { media: screen }
+      css/components/dropbutton.component.css: { media: screen }
+      css/components/entity-meta.css: { media: screen }
+      css/components/field-ui.css: { media: screen }
+      css/components/form.css: { media: screen }
+      css/components/help.css: { media: screen }
+      css/components/menus-and-lists.css: { media: screen }
+      css/components/modules-page.css: { media: screen }
+      css/components/node.css: { media: screen }
+      css/components/page-title.css: { media: screen }
+      css/components/pager.css: { media: screen }
+      css/components/skip-link.css: { media: screen }
+      css/components/tables.css: { media: screen }
+      css/components/tabs.css: { media: screen }
+      css/components/tour.theme.css: { media: screen }
+      css/components/update-status.css: { media: screen }
+      css/components/views-ui.css: { media: screen }
+      css/layout/layout.css: { media: screen }
+      css/layout/node-add.css: { media: screen }
+      css/theme/appearance-page.css: { media: screen }
+
 maintenance-page:
   version: VERSION
   js:
@@ -7,6 +43,7 @@ maintenance-page:
       css/theme/maintenance-page.css: {}
   dependencies:
     - system/maintenance
+    - seven/base
 
 install-page:
   version: VERSION