diff --git a/modules/custom/d8_night/config/install/d8_night.settings.yml b/modules/custom/d8_night/config/install/d8_night.settings.yml
index 32462791..ea928e28 100644
--- a/modules/custom/d8_night/config/install/d8_night.settings.yml
+++ b/modules/custom/d8_night/config/install/d8_night.settings.yml
@@ -1 +1 @@
-theme: 'slate'
+cdn_theme: 'slate'
diff --git a/modules/custom/d8_night/config/schema/d8_night.schema.yml b/modules/custom/d8_night/config/schema/d8_night.schema.yml
index 40ac371c..0569f4be 100644
--- a/modules/custom/d8_night/config/schema/d8_night.schema.yml
+++ b/modules/custom/d8_night/config/schema/d8_night.schema.yml
@@ -4,6 +4,6 @@ d8_night.settings:
   type: config_object
   label: 'D8+ Night settings'
   mapping:
-    text:
+    cdn_theme:
       type: string
       label: 'Bootstrap CDN theme for dark mode'
diff --git a/modules/custom/d8_night/d8_night.module b/modules/custom/d8_night/d8_night.module
index bb1ff3c9..6d270ae4 100644
--- a/modules/custom/d8_night/d8_night.module
+++ b/modules/custom/d8_night/d8_night.module
@@ -8,6 +8,7 @@
 use Drupal\bootstrap\Bootstrap;
 use Drupal\Core\Block\BlockPluginInterface;
 use Drupal\Core\Routing\RouteMatchInterface;
+use Drupal\d8_night\Form\D8NightForm;
 
 /**
  * Implements hook_block_view_BASE_BLOCK_ID_alter().
@@ -18,8 +19,8 @@ function d8_night_block_view_dark_mode_switch_block_alter(
 ) {
   $build['#attached']['library'][] = 'd8_night/base';
 
-  $active_theme = Bootstrap::getTheme('d8_theme')->getSetting('cdn_theme');
-  $needed_theme = \Drupal::config('d8_night.settings')->get('theme');
+  $active_theme = Bootstrap::getTheme('d8_theme')->getSetting(D8NightForm::NAME);
+  $needed_theme = \Drupal::config('d8_night.settings')->get(D8NightForm::NAME);
   $build['#attached']['drupalSettings']['d8_night'] = $active_theme === $needed_theme;
 }
 
diff --git a/modules/custom/d8_night/src/Controller/D8NightController.php b/modules/custom/d8_night/src/Controller/D8NightController.php
index 6c20ac52..11e906d0 100644
--- a/modules/custom/d8_night/src/Controller/D8NightController.php
+++ b/modules/custom/d8_night/src/Controller/D8NightController.php
@@ -4,6 +4,7 @@
 
 use Drupal\bootstrap\Bootstrap;
 use Drupal\Core\Controller\ControllerBase;
+use Drupal\d8_night\Form\D8NightForm;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\HttpFoundation\JsonResponse;
 
@@ -12,6 +13,13 @@
  */
 class D8NightController extends ControllerBase {
 
+  /**
+   * The cache tags invalidator.
+   *
+   * @var \Drupal\Core\Cache\CacheTagsInvalidatorInterface
+   */
+  private $invalidator;
+
   /**
    * {@inheritdoc}
    */
@@ -19,6 +27,7 @@ public static function create(ContainerInterface $container) {
     $instance = parent::create($container);
 
     $instance->configFactory = $container->get('config.factory');
+    $instance->invalidator = $container->get('cache_tags.invalidator');
 
     return $instance;
   }
@@ -36,13 +45,21 @@ public static function create(ContainerInterface $container) {
    *   The JSON response.
    */
   public function switch($mode) {
-    $theme = Bootstrap::getTheme('d8_theme');
-    $sub_theme = $this->config('d8_night.settings')->get('theme');
-    $was = $theme->getSetting('cdn_theme') === $sub_theme;
+    $settings = ($theme = Bootstrap::getTheme('d8_theme'))->settings();
+    $sub_theme = $this->config('d8_night.settings')->get(D8NightForm::NAME);
+    $was = $settings->get(D8NightForm::NAME) === $sub_theme;
 
     if ($update = ($now = !empty($mode)) !== $was) {
-      $theme->setSetting('cdn_theme', $now ? $sub_theme : 'bootstrap');
-      drupal_flush_all_caches();
+      $settings
+        ->set(D8NightForm::NAME, $now ? $sub_theme : 'bootstrap')
+        ->clear('cdn_cache')
+        ->save();
+
+      if ($tags = $theme->getSettingPlugin(D8NightForm::NAME)->getCacheTags()) {
+        $this->invalidator->invalidateTags($tags);
+      }
+
+      $theme->getCache('settings')->deleteAll();
     }
 
     return new JsonResponse(['update' => $update]);
diff --git a/modules/custom/d8_night/src/Form/D8NightForm.php b/modules/custom/d8_night/src/Form/D8NightForm.php
index 4b870065..89eadb50 100644
--- a/modules/custom/d8_night/src/Form/D8NightForm.php
+++ b/modules/custom/d8_night/src/Form/D8NightForm.php
@@ -2,14 +2,21 @@
 
 namespace Drupal\d8_night\Form;
 
+use Drupal\bootstrap\Bootstrap;
 use Drupal\Core\Form\ConfigFormBase;
 use Drupal\Core\Form\FormStateInterface;
+use Drupal\Core\Render\Element;
 
 /**
  * Configure D8+ Night settings for this site.
  */
 class D8NightForm extends ConfigFormBase {
 
+  /**
+   * The Bootstrap CDN theme setting name.
+   */
+  const NAME = 'cdn_theme';
+
   /**
    * {@inheritdoc}
    */
@@ -28,14 +35,18 @@ public function getFormId() {
    * {@inheritdoc}
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
-    $form['theme'] = [
-      '#type' => 'select',
-      '#title' => $this->t('Theme'),
-      '#description' => $this->t('Bootstrap CDN theme for dark mode.'),
-      '#options' => [],
-      '#default_value' => $this->config($this->getEditableConfigNames()[0])
-        ->get('theme'),
-    ];
+    Bootstrap::getTheme('d8_theme')->getSettingPlugin(self::NAME)
+      ->alterForm(
+        $form,
+        $form_state->setValue(
+          self::NAME,
+          $this->config($this->getEditableConfigNames()[0])->get(self::NAME)
+        )
+      );
+
+    foreach (Element::children($form) as $key) {
+      $form[$key]['#type'] = 'container';
+    }
 
     return parent::buildForm($form, $form_state);
   }
@@ -45,7 +56,7 @@ public function buildForm(array $form, FormStateInterface $form_state) {
    */
   public function submitForm(array &$form, FormStateInterface $form_state) {
     $this->config($this->getEditableConfigNames()[0])
-      ->set('theme', $form_state->getValue('theme'))
+      ->set(self::NAME, $form_state->getValue(self::NAME))
       ->save();
 
     parent::submitForm($form, $form_state);