Issue #3279640 by alexpott, Spokje, mherchel, lauriii, catch: Standard install profile uses Olivero for update.php

core/modules/system/src/Theme/DbUpdateNegotiator.php

@@ -3,6 +3,7 @@
 namespace Drupal\system\Theme;
 
 use Drupal\Core\Config\ConfigFactoryInterface;
+use Drupal\Core\Extension\ThemeHandlerInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
 use Drupal\Core\Site\Settings;
 use Drupal\Core\Theme\ThemeNegotiatorInterface;
@@ -19,14 +20,24 @@ class DbUpdateNegotiator implements ThemeNegotiatorInterface {
    */
   protected $configFactory;
 
+  /**
+   * The theme handler.
+   *
+   * @var \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected $themeHandler;
+
   /**
    * Constructs a DbUpdateNegotiator.
    *
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The config factory.
+   * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
+   *   The theme handler.
    */
-  public function __construct(ConfigFactoryInterface $config_factory) {
+  public function __construct(ConfigFactoryInterface $config_factory, ThemeHandlerInterface $theme_handler) {
     $this->configFactory = $config_factory;
+    $this->themeHandler = $theme_handler;
   }
 
   /**
@@ -40,10 +51,9 @@ class DbUpdateNegotiator implements ThemeNegotiatorInterface {
    * {@inheritdoc}
    */
   public function determineActiveTheme(RouteMatchInterface $route_match) {
-    $custom_theme = Settings::get('maintenance_theme', 'seven');
+    $custom_theme = Settings::get('maintenance_theme');
     if (!$custom_theme) {
-      $config = $this->configFactory->get('system.theme');
-      $custom_theme = $config->get('default');
+      $custom_theme = $this->themeHandler->themeExists('claro') ? 'claro' : 'seven';
     }
 
     return $custom_theme;

core/modules/system/system.services.yml

@@ -30,7 +30,7 @@ services:
       - { name: theme_negotiator, priority: 1000 }
   theme.negotiator.system.db_update:
     class: Drupal\system\Theme\DbUpdateNegotiator
-    arguments: ['@config.factory']
+    arguments: ['@config.factory', '@theme_handler']
     tags:
       - { name: theme_negotiator, priority: 100 }
   system.config_subscriber:

core/themes/claro/css/theme/maintenance-page.css

@@ -15,6 +15,10 @@
   background-color: var(--color-gray-100);
 }
 
+.title {
+  margin-top: 0;
+}
+
 .site-name {
   margin-top: var(--space-m);
   word-wrap: break-word;
@@ -179,6 +183,19 @@
   [dir="rtl"] .layout-sidebar-first {
     float: right;
   }
+  /* Positioning sidebar & content */
+  main {
+    float: left; /* LTR */
+    clear: none;
+    box-sizing: border-box;
+    width: 65%;
+    padding-left: 3.85em; /* LTR */
+  }
+  [dir="rtl"] main {
+    float: right;
+    padding-right: 3.85em;
+    padding-left: 0;
+  }
 }
 
 /**

core/themes/claro/css/theme/maintenance-page.pcss.css

@@ -8,6 +8,10 @@
   background-color: var(--color-gray-100);
 }
 
+.title {
+  margin-top: 0;
+}
+
 .site-name {
   margin-top: var(--space-m);
   word-wrap: break-word;
@@ -169,6 +173,19 @@
   [dir="rtl"] .layout-sidebar-first {
     float: right;
   }
+  /* Positioning sidebar & content */
+  main {
+    float: left; /* LTR */
+    clear: none;
+    box-sizing: border-box;
+    width: 65%;
+    padding-left: 3.85em; /* LTR */
+  }
+  [dir="rtl"] main {
+    float: right;
+    padding-right: 3.85em;
+    padding-left: 0;
+  }
 }
 
 /**