diff --git a/README.md b/README.md
index 8e90774ff..d53ad9c2b 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,7 @@ This installation profile requires the following extensions:
 - [Admin Toolbar](https://www.drupal.org/project/admin_toolbar)
 - [Automatic IP ban (Autoban)](https://www.drupal.org/project/autoban)
 - [Bootstrap](https://www.drupal.org/project/bootstrap)
+- [Bootstrap Light-Dark-Color Theme Mode Toggler](https://www.drupal.org/project/bootstrap_theme_toggler)
 - [CAPTCHA](https://www.drupal.org/project/captcha)
 - [Config Export to PHP array](https://www.drupal.org/project/config2php)
 - [Configuration Update Manager](https://www.drupal.org/project/config_update)
diff --git a/composer.json b/composer.json
index 5c6f5d5a6..f509d91da 100644
--- a/composer.json
+++ b/composer.json
@@ -9,6 +9,7 @@
         "drupal/admin_toolbar": "3.6.2",
         "drupal/autoban": "1.11",
         "drupal/bootstrap": ">=5.0.0",
+        "drupal/bootstrap_theme_toggler": "dev-project-update-bot-only",
         "drupal/captcha": "2.0.10",
         "drupal/config_update": "2.0.0-alpha4",
         "drupal/core": "11.3.1",
@@ -57,8 +58,23 @@
     },
     "repositories": [
         {
+            "canonical": false,
             "type": "composer",
             "url": "https://packages.drupal.org/8"
+        },
+        {
+            "canonical": false,
+            "type": "package",
+            "package": {
+                "name": "drupal/bootstrap_theme_toggler",
+                "version": "dev-project-update-bot-only",
+                "type": "drupal-module",
+                "source": {
+                    "url": "https://git.drupalcode.org/issue/bootstrap_theme_toggler-3428288.git",
+                    "type": "git",
+                    "reference": "ac617b8946b72d0d85d44d4c19540ccbee03da2f"
+                }
+            }
         }
     ]
 }
diff --git a/d8.info.yml b/d8.info.yml
index 0889c9b9b..e0a1b85c0 100644
--- a/d8.info.yml
+++ b/d8.info.yml
@@ -29,6 +29,7 @@ install:
 
   - admin_toolbar:admin_toolbar_search
   - admin_toolbar:admin_toolbar_tools
+  - bootstrap_theme_toggler:bootstrap_theme_toggler
   - features:features_ui
   - idle:idle (>=1.0.2)
   - module_filter:module_filter
diff --git a/d8.install b/d8.install
index dea4711a6..daaee0c42 100644
--- a/d8.install
+++ b/d8.install
@@ -45,6 +45,13 @@ function d8_update_last_removed(): int {
   return 11201;
 }
 
+/**
+ * Install Bootstrap Light-Dark-Color Theme Mode Toggler module.
+ */
+function d8_update_11301(array &$sandbox): void {
+  \Drupal::classResolver(D8Setup::class)->module('bootstrap_theme_toggler');
+}
+
 /**
  * Process list of update hooks.
  *
diff --git a/modules/features/d8_captcha/js/recaptcha.invisible.js b/modules/features/d8_captcha/js/recaptcha.js
similarity index 100%
rename from modules/features/d8_captcha/js/recaptcha.invisible.js
rename to modules/features/d8_captcha/js/recaptcha.js
diff --git a/modules/features/d8_captcha/js/recaptcha_preloader.js b/modules/features/d8_captcha/js/recaptcha_preloader.js
new file mode 100644
index 000000000..09905f6ae
--- /dev/null
+++ b/modules/features/d8_captcha/js/recaptcha_preloader.js
@@ -0,0 +1,51 @@
+((window, document, $) => {
+
+  'use strict';
+
+  const query = window.matchMedia('(prefers-color-scheme: dark)');
+
+  window.onLoadReCaptcha = () => {
+    document.querySelectorAll('.g-recaptcha').forEach(el => {
+      const key = el.dataset.sitekey;
+      const themes = {true: 'dark', false: 'light'};
+      const dark = el.dataset.theme === themes[true];
+      const container = el.cloneNode(false);
+
+      if (query.matches !== dark) {
+        const preloader = el.nextElementSibling.classList;
+
+        preloader.remove(el.dataset.theme);
+        preloader.add(themes[!dark]);
+      }
+
+      el.parentNode.replaceChild(container, el);
+
+      window.grecaptcha.render(container, {
+        sitekey: key,
+        theme: themes[query.matches],
+      });
+
+      const observer = new MutationObserver(() => {
+        if (container.querySelector('iframe')) {
+          observer.disconnect();
+
+          $(container)
+            .closest('.g-recaptcha-wrapper')
+            .removeClass('loading')
+            .closest('form')
+            .find('.blocked-by-recaptcha')
+            .removeAttr('disabled')
+            .removeClass('blocked-by-recaptcha is-disabled');
+        }
+      });
+
+      observer.observe(container, {
+        childList: true,
+        subtree: true,
+      });
+    });
+  }
+
+  query.addEventListener('change', window.onLoadReCaptcha);
+
+})(window, document, jQuery);
diff --git a/modules/features/d8_captcha/src/Hook/D8CaptchaHooks.php b/modules/features/d8_captcha/src/Hook/D8CaptchaHooks.php
index a09fd9e62..ac61b4c40 100644
--- a/modules/features/d8_captcha/src/Hook/D8CaptchaHooks.php
+++ b/modules/features/d8_captcha/src/Hook/D8CaptchaHooks.php
@@ -14,6 +14,16 @@
  */
 final class D8CaptchaHooks extends D8HooksBase {
 
+  /**
+   * The URL prefix for the Google reCAPTCHA API script.
+   */
+  private const string PREFIX = 'https://www.google.com/recaptcha/api.js?';
+
+  /**
+   * The triggered function name for the Google reCAPTCHA API script.
+   */
+  private const string SUFFIX = 'onload=onLoadReCaptcha';
+
   /**
    * D8CaptchaHooks constructor.
    *
@@ -62,10 +72,37 @@ public function libraryInfoAlter(array &$libraries, string $extension): void {
       $extension === 'recaptcha' &&
       isset($libraries[$name = "$extension.invisible"])
     ) {
-      $path = $this->extensionPathResolver->getPath('module', 'd8_captcha');
+      $libraries[$name]['js'] = [$this->path($extension) => []];
+    }
+    elseif ($extension === 'recaptcha_preloader') {
+      $items = &$libraries['connector']['js'];
+
+      $replacements = [
+        'js/base.js' => $this->path($extension),
+        self::PREFIX . self::SUFFIX
+          => self::PREFIX . 'render=explicit&' . self::SUFFIX,
+      ];
 
-      $libraries[$name]['js'] = ["/$path/js/$name.js" => []];
+      foreach ($replacements as $old => $new) {
+        $items[$new] = $items[$old];
+
+        unset($items[$old]);
+      }
     }
   }
 
+  /**
+   * Generates a JavaScript file path for the specified file name.
+   *
+   * @param string $name
+   *   The name of the JavaScript file (without extension).
+   */
+  private function path(string $name): string {
+    return sprintf(
+      '/%s/js/%s.js',
+      $this->extensionPathResolver->getPath('module', 'd8_captcha'),
+      $name,
+    );
+  }
+
 }
diff --git a/modules/features/d8_theming/config/install/d8_theme.settings.yml b/modules/features/d8_theming/config/install/d8_theme.settings.yml
index 819a00126..a690bde0a 100644
--- a/modules/features/d8_theming/config/install/d8_theme.settings.yml
+++ b/modules/features/d8_theming/config/install/d8_theme.settings.yml
@@ -59,7 +59,7 @@ bootstrap_navbar_top_color: ''
 bootstrap_navbar_top_background: ''
 bootstrap_navbar_position: ''
 bootstrap_navbar_color: ''
-bootstrap_navbar_background: bg-light
+bootstrap_navbar_background: bg-body-tertiary
 bootstrap_navbar_top_class: ''
 bootstrap_navbar_class: 'order-last order-sm-first mt-auto mt-sm-0'
 bootstrap_navbar_offcanvas: ''
diff --git a/themes/custom/d8_theme/config/install/d8_theme.settings.yml b/themes/custom/d8_theme/config/install/d8_theme.settings.yml
index 819a00126..a690bde0a 100644
--- a/themes/custom/d8_theme/config/install/d8_theme.settings.yml
+++ b/themes/custom/d8_theme/config/install/d8_theme.settings.yml
@@ -59,7 +59,7 @@ bootstrap_navbar_top_color: ''
 bootstrap_navbar_top_background: ''
 bootstrap_navbar_position: ''
 bootstrap_navbar_color: ''
-bootstrap_navbar_background: bg-light
+bootstrap_navbar_background: bg-body-tertiary
 bootstrap_navbar_top_class: ''
 bootstrap_navbar_class: 'order-last order-sm-first mt-auto mt-sm-0'
 bootstrap_navbar_offcanvas: ''
diff --git a/themes/custom/d8_theme/src/Hook/D8ThemeHooks.php b/themes/custom/d8_theme/src/Hook/D8ThemeHooks.php
index 4c4b968bc..63ea43205 100644
--- a/themes/custom/d8_theme/src/Hook/D8ThemeHooks.php
+++ b/themes/custom/d8_theme/src/Hook/D8ThemeHooks.php
@@ -10,6 +10,31 @@
  */
 final class D8ThemeHooks {
 
+  /**
+   * Implements hook_form_FORM_ID_alter().
+   */
+  #[Hook('form_system_theme_settings_alter')]
+  public function formSystemThemeSettingsAlter(
+    array &$form,
+    FormStateInterface $form_state,
+    ?string $form_id = NULL,
+  ): void {
+    $group = &$form['components']['navbar'];
+
+    $old = &$group['bootstrap_navbar_background']['#options'];
+    $new = [];
+
+    foreach ($old as $class => $label) {
+      $new[$class === 'bg-light' ? 'bg-body-tertiary' : $class] = $label;
+    }
+
+    $old = $new;
+
+    foreach (['maxlength', 'size'] as $key) {
+      $group['bootstrap_navbar_class']["#$key"] = 50;
+    }
+  }
+
   /**
    * Implements hook_form_FORM_ID_alter().
    */