diff --git a/composer.json b/composer.json
index c55d925d..b00b4d0e 100644
--- a/composer.json
+++ b/composer.json
@@ -28,6 +28,7 @@
         "drupal/gin": "^4.0.6",
         "drupal/gin_toolbar": "^2",
         "drupal/google_tag": "^2.0.9",
+        "drupal/highlight_js": "^1.2",
         "drupal/lagoon_logs": "^3.0.1",
         "drupal/metatag": "^2.2",
         "drupal/pathauto": "^1.14",
diff --git a/composer.lock b/composer.lock
index 3abe2fad..7a6d0d27 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "ce081e63b3639ce500037147a974b7aa",
+    "content-hash": "568d8e68ffbeedad71d925da755e5339",
     "packages": [
         {
             "name": "asm89/stack-cors",
@@ -3705,6 +3705,58 @@
                 "source": "https://git.drupalcode.org/project/google_tag"
             }
         },
+        {
+            "name": "drupal/highlight_js",
+            "version": "1.2.0",
+            "source": {
+                "type": "git",
+                "url": "https://git.drupalcode.org/project/highlight_js.git",
+                "reference": "1.2.0"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://ftp.drupal.org/files/projects/highlight_js-1.2.0.zip",
+                "reference": "1.2.0",
+                "shasum": "ae389f3a03ee09d4dcb83cd3d731e6910bfe1a5c"
+            },
+            "require": {
+                "drupal/core": "^9 || ^10 || ^11"
+            },
+            "type": "drupal-module",
+            "extra": {
+                "drupal": {
+                    "version": "1.2.0",
+                    "datestamp": "1763546332",
+                    "security-coverage": {
+                        "status": "covered",
+                        "message": "Covered by Drupal's security advisory policy"
+                    }
+                }
+            },
+            "notification-url": "https://packages.drupal.org/8/downloads",
+            "license": [
+                "GPL-2.0-or-later"
+            ],
+            "authors": [
+                {
+                    "name": "a.dmitriiev",
+                    "homepage": "https://www.drupal.org/user/3235287"
+                },
+                {
+                    "name": "norman.lol",
+                    "homepage": "https://www.drupal.org/user/2482808"
+                },
+                {
+                    "name": "sujan shrestha",
+                    "homepage": "https://www.drupal.org/user/3475737"
+                }
+            ],
+            "description": "Adds the HighlightJs plugin to CKEditor 5 with syntax highlighting provided by HighlightJs.",
+            "homepage": "https://www.drupal.org/project/highlight_js",
+            "support": {
+                "source": "https://git.drupalcode.org/project/highlight_js"
+            }
+        },
         {
             "name": "drupal/key",
             "version": "1.22.0",
diff --git a/config/default/core.extension.yml b/config/default/core.extension.yml
index 8e58d412..ed0b2b45 100644
--- a/config/default/core.extension.yml
+++ b/config/default/core.extension.yml
@@ -47,6 +47,7 @@ module:
   gin_toolbar: 0
   google_tag: 0
   help: 0
+  highlight_js: 0
   history: 0
   image: 0
   image_captcha: 0
diff --git a/config/default/editor.editor.civictheme_rich_text.yml b/config/default/editor.editor.civictheme_rich_text.yml
index c919942b..434361a5 100644
--- a/config/default/editor.editor.civictheme_rich_text.yml
+++ b/config/default/editor.editor.civictheme_rich_text.yml
@@ -6,6 +6,7 @@ dependencies:
     - filter.format.civictheme_rich_text
   module:
     - ckeditor5
+    - highlight_js
 _core:
   default_config_hash: SztHd9Hrw3-1EuKex-O6V-Kc5EpxLGsSam2HEDXSgDM
 format: civictheme_rich_text
@@ -40,6 +41,8 @@ settings:
       - subscript
       - '|'
       - sourceEditing
+      - '|'
+      - highlightJs
   plugins:
     ckeditor5_alignment:
       enabled_alignments:
diff --git a/config/default/filter.format.civictheme_rich_text.yml b/config/default/filter.format.civictheme_rich_text.yml
index 1c920ed0..625d36e5 100644
--- a/config/default/filter.format.civictheme_rich_text.yml
+++ b/config/default/filter.format.civictheme_rich_text.yml
@@ -6,6 +6,7 @@ dependencies:
     - core.entity_view_mode.media.embedded
   module:
     - editor
+    - highlight_js
     - linkit
     - media
 _core:
@@ -44,7 +45,7 @@ filters:
     status: true
     weight: -50
     settings:
-      allowed_html: '<br> <p class="ct-text-large ct-text-small text-align-left text-align-center text-align-right"> <h2 id class> <h3 id class="text-align-left text-align-center text-align-right"> <h4 id class="text-align-left text-align-center text-align-right"> <h5 id class="text-align-left text-align-center text-align-right"> <h6 id class="text-align-left text-align-center text-align-right"> <a class="ct-button ct-theme-light ct-theme-dark ct-button--primary ct-button--regular ct-button--secondary ct-button--large" hreflang target title href data-entity-type data-entity-uuid data-entity-substitution> <table class="ct-theme-light ct-theme-dark ct-table ct-table--striped"> <cite> <dl> <dt> <dd> <img src alt data-entity-type data-entity-uuid> <drupal-entity alt title data-entity-type data-entity-uuid data-entity-embed-display data-entity-embed-display-settings data-align data-caption data-embed-button> <span class="ct-visually-hidden"> <svg role viewBox aria-hidden width height class="ct-icon"> <path d> <blockquote cite> <drupal-media title data-entity-type data-entity-uuid alt data-caption data-align> <strong> <em> <u> <code class="language-*"> <pre class="text-align-left text-align-center text-align-right"> <s> <sub> <sup> <ul type> <ol type start> <li> <tr> <td rowspan colspan> <th rowspan colspan> <thead> <tbody> <tfoot> <caption>'
+      allowed_html: '<br> <p class="ct-text-large ct-text-small text-align-left text-align-center text-align-right"> <h2 id class> <h3 id class="text-align-left text-align-center text-align-right"> <h4 id class="text-align-left text-align-center text-align-right"> <h5 id class="text-align-left text-align-center text-align-right"> <h6 id class="text-align-left text-align-center text-align-right"> <a class="ct-button ct-theme-light ct-theme-dark ct-button--primary ct-button--regular ct-button--secondary ct-button--large" hreflang target title href data-entity-type data-entity-uuid data-entity-substitution> <table class="ct-theme-light ct-theme-dark ct-table ct-table--striped"> <cite> <dl> <dt> <dd> <img src alt data-entity-type data-entity-uuid> <drupal-entity alt title data-entity-type data-entity-uuid data-entity-embed-display data-entity-embed-display-settings data-align data-caption data-embed-button> <span class="ct-visually-hidden"> <svg role viewBox aria-hidden width height class="ct-icon"> <path d> <blockquote cite> <drupal-media title data-entity-type data-entity-uuid alt data-caption data-align> <strong> <em> <u> <code class="language-*"> <pre class="text-align-left text-align-center text-align-right"> <s> <sub> <sup> <ul type> <ol type start> <li> <tr> <td rowspan colspan> <th rowspan colspan> <thead> <tbody> <tfoot> <caption> <highlight-js data-plugin-config data-plugin-id>'
       filter_html_help: true
       filter_html_nofollow: false
   filter_html_escape:
@@ -72,6 +73,12 @@ filters:
     weight: -44
     settings:
       filter_url_length: 72
+  highlight_js:
+    id: highlight_js
+    provider: highlight_js
+    status: true
+    weight: -40
+    settings: {  }
   linkit:
     id: linkit
     provider: linkit
diff --git a/config/default/highlight_js.settings.yml b/config/default/highlight_js.settings.yml
new file mode 100644
index 00000000..89342203
--- /dev/null
+++ b/config/default/highlight_js.settings.yml
@@ -0,0 +1,12 @@
+copy_enable: true
+copy_bg_transparent: false
+copy_bg_color: '#4243b1'
+copy_txt_color: '#ffffff'
+copy_btn_text: ''
+copy_success_text: ''
+success_txt_color: '#ffffff'
+role_copy_access: {  }
+languages: {  }
+theme: github
+success_bg_transparent: false
+success_bg_color: '#4243b1'
diff --git a/config/default/seckit.settings.yml b/config/default/seckit.settings.yml
index 5c8db19a..029bdb3b 100644
--- a/config/default/seckit.settings.yml
+++ b/config/default/seckit.settings.yml
@@ -8,7 +8,7 @@ seckit_xss:
     default-src: "'self'"
     script-src: "'self' https://www.googletagmanager.com https://www.gstatic.com https://www.recaptcha.net https://www.google.com https://cdnjs.cloudflare.com https://cdn.jsdelivr.net/gh/cferdinandi/tabby@12.0.3/dist/js/tabby.min.js https://unpkg.com/@popperjs/core@2.11.6/dist/umd/popper.js https://unpkg.com/tippy.js@6.3.7/dist/tippy.umd.js"
     object-src: "'none'"
-    style-src: "'self' 'unsafe-inline' https://fonts.googleapis.com/ https://cdn.jsdelivr.net/gh/cferdinandi/tabby@12.0.3/dist/css/tabby-ui.min.css https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.12/codemirror.css https://unpkg.com/tippy.js@6.3.7/dist/tippy.css https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/css/select2.min.css"
+    style-src: "'self' https://cdnjs.cloudflare.com/ajax/libs/highlight.js/ 'unsafe-inline' https://fonts.googleapis.com/ https://cdn.jsdelivr.net/gh/cferdinandi/tabby@12.0.3/dist/css/tabby-ui.min.css https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.12/codemirror.css https://unpkg.com/tippy.js@6.3.7/dist/tippy.css https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/css/select2.min.css"
     img-src: "'self' data:"
     media-src: "'self'"
     frame-src: "'self' https://www.youtube.com https://www.recaptcha.net https://www.google.com"
diff --git a/tests/behat/features/seckit.feature b/tests/behat/features/seckit.feature
index 5108a8e0..5094c44e 100644
--- a/tests/behat/features/seckit.feature
+++ b/tests/behat/features/seckit.feature
@@ -17,7 +17,7 @@ Feature: Seckit
     And the response header "Content-Security-Policy" should contain the value "media-src 'self'"
     And the response header "Content-Security-Policy" should contain the value "report-uri /report-csp-violation"
     And the response header "Content-Security-Policy" should contain the value "script-src 'self' https://www.googletagmanager.com https://www.gstatic.com https://www.recaptcha.net https://www.google.com https://cdnjs.cloudflare.com https://cdn.jsdelivr.net/gh/cferdinandi/tabby@12.0.3/dist/js/tabby.min.js https://unpkg.com/@popperjs/core@2.11.6/dist/umd/popper.js https://unpkg.com/tippy.js@6.3.7/dist/tippy.umd.js;"
-    And the response header "Content-Security-Policy" should contain the value "style-src 'self' 'unsafe-inline' https://fonts.googleapis.com/ https://cdn.jsdelivr.net/gh/cferdinandi/tabby@12.0.3/dist/css/tabby-ui.min.css https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.12/codemirror.css https://unpkg.com/tippy.js@6.3.7/dist/tippy.css https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/css/select2.min.css;"
+    And the response header "Content-Security-Policy" should contain the value "style-src 'self' https://cdnjs.cloudflare.com/ajax/libs/highlight.js/ 'unsafe-inline' https://fonts.googleapis.com/ https://cdn.jsdelivr.net/gh/cferdinandi/tabby@12.0.3/dist/css/tabby-ui.min.css https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.65.12/codemirror.css https://unpkg.com/tippy.js@6.3.7/dist/tippy.css https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.13/css/select2.min.css;"
     And the response header "Strict-Transport-Security" should contain the value "max-age=31536000"
     And the response header "Strict-Transport-Security" should contain the value "includeSubDomains"
     And the response header "Strict-Transport-Security" should contain the value "preload"
diff --git a/web/modules/custom/do_base/do_base.libraries.yml b/web/modules/custom/do_base/do_base.libraries.yml
new file mode 100644
index 00000000..8fb82d57
--- /dev/null
+++ b/web/modules/custom/do_base/do_base.libraries.yml
@@ -0,0 +1,5 @@
+highlight_js.gherkin:
+  js:
+    https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/languages/gherkin.min.js: { type: external, minified: true }
+  dependencies:
+    - highlight_js/highlight_js.js
diff --git a/web/modules/custom/do_base/src/Hook/LibraryInfoAlterHook.php b/web/modules/custom/do_base/src/Hook/LibraryInfoAlterHook.php
new file mode 100644
index 00000000..98736981
--- /dev/null
+++ b/web/modules/custom/do_base/src/Hook/LibraryInfoAlterHook.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\do_base\Hook;
+
+use Drupal\Core\Hook\Attribute\Hook;
+
+/**
+ * Library info alter hooks for do_base module.
+ */
+final class LibraryInfoAlterHook {
+
+  /**
+   * Implements hook_library_info_alter().
+   *
+   * Attaches Gherkin language support whenever Highlight.js is loaded.
+   * The CDN common bundle does not include Gherkin, so we load it separately.
+   */
+  #[Hook('library_info_alter')]
+  public function alter(array &$libraries, string $extension): void {
+    if ($extension === 'highlight_js' && isset($libraries['highlight_js.custom'])) {
+      $libraries['highlight_js.custom']['dependencies'][] = 'do_base/highlight_js.gherkin';
+    }
+  }
+
+}