diff --git a/src/Integrations/Divi/Compose/AttrWriter.php b/src/Integrations/Divi/Compose/AttrWriter.php
index 2c2e528..3a71f70 100644
--- a/src/Integrations/Divi/Compose/AttrWriter.php
+++ b/src/Integrations/Divi/Compose/AttrWriter.php
@@ -35,10 +35,11 @@ final class AttrWriter
     private const URL_SEGMENT = '/url$/i';
 
     /**
-     * Raw HTML/CSS fields, and the ones Divi re-serializes whole pages for (ruling S7), at any
-     * depth: module.advanced.html, module.advanced.html.htmlBefore, css.advanced.customCss.
+     * Raw HTML/CSS fields, and the ones Divi re-serializes whole pages for (rulings S7/S26), by
+     * path shape at any depth: module.advanced.html(.htmlBefore), module.decoration.attributes,
+     * any free-form custom CSS path of any module (css, css.*, title.css.*, css.advanced.customCss).
      */
-    private const BUILDER_ONLY = '/(^|\.)(decoration\.attributes|advanced\.html|advanced\.customCss)(\.|$)/';
+    private const BUILDER_ONLY = '/(^|\.)(decoration\.attributes|advanced\.html|advanced\.customCss|css)(\.|$)/';
 
     public function __construct(
         private ModuleCatalog $catalog,
diff --git a/src/Integrations/Divi/Compose/VariableRef.php b/src/Integrations/Divi/Compose/VariableRef.php
index 65fc4f4..eb7a945 100644
--- a/src/Integrations/Divi/Compose/VariableRef.php
+++ b/src/Integrations/Divi/Compose/VariableRef.php
@@ -22,7 +22,7 @@ use stdClass;
  * Allowed names:
  * - type "color": a global color ID of the design system or a global variable of type "colors";
  *   settings hue/saturation/lightness/opacity, numbers only.
- * - type "content": a non-color global variable or a theme font (settings DESIGN_SETTINGS);
+ * - type "content": a non-color global variable or a theme font (no settings, DESIGN_SETTINGS, S27);
  *   custom_meta_<key> with META_KEY (no leading "_", ruling S12; settings from the map entry of
  *   that exact name, else META_SETTINGS); or a key of the dynamic content map.
  *
@@ -59,8 +59,13 @@ final class VariableRef
     /** Settings of custom_meta_<key> without a map entry of its own. */
     public const META_SETTINGS = self::BEFORE_AFTER;
 
-    /** Settings of content references to global variables and theme fonts. */
-    public const DESIGN_SETTINGS = self::BEFORE_AFTER;
+    /**
+     * Settings of content references to global variables and theme fonts: none (ruling S27).
+     * Divi ignores them: theme fonts resolve to var(<name>) (DynamicData.php:300), and the gvid
+     * option "doesn't have any settings" and renders without them
+     * (DynamicContentGlobalVariableOptions.php:66-69, 155-161).
+     */
+    public const DESIGN_SETTINGS = [];
 
     private const BEFORE_AFTER = ['before' => 'richtext', 'after' => 'richtext'];
 
diff --git a/tests/Unit/Integrations/Divi/Compose/AttrWriterTest.php b/tests/Unit/Integrations/Divi/Compose/AttrWriterTest.php
index f2082af..1291fdd 100644
--- a/tests/Unit/Integrations/Divi/Compose/AttrWriterTest.php
+++ b/tests/Unit/Integrations/Divi/Compose/AttrWriterTest.php
@@ -263,6 +263,26 @@ final class AttrWriterTest extends TestCase
         ComposeFixture::attrWriter()->cleanValue('divi/button', 'module.decoration.attributes', ['attributes' => []]);
     }
 
+    /** Ruling S26: every free-form custom CSS path (css.*) is builder-only for editors, by path shape. */
+    public function testCustomCssPathsNeedUnfilteredHtml(): void
+    {
+        $css = ['mainElement' => 'color:red;} body{display:none'];
+        foreach (['css', 'css.desktop', 'css.advanced.customCss', 'css.advanced.mainElement', 'title.css'] as $path) {
+            try {
+                ComposeFixture::attrWriter()->cleanValue('divi/text', $path, $css);
+                self::fail('Accepted for an editor: ' . $path);
+            } catch (InvalidArgumentException $e) {
+                self::assertStringContainsString('nur im Divi-Builder', $e->getMessage());
+            }
+
+            self::assertSame($css, ComposeFixture::attrWriter(true)->cleanValue('divi/text', $path, $css));
+        }
+
+        // Only a whole "css" segment counts.
+        self::assertSame('x', ComposeFixture::attrWriter()->cleanValue('divi/text', 'module.advanced.cssClass', 'x'));
+        self::assertSame('x', ComposeFixture::attrWriter()->cleanValue('divi/text', 'module.cssish', 'x'));
+    }
+
     /** Ruling S23: content.innerContent of unknown kind (defined only in Divi's JS) is rich text. */
     public function testUnknownContentInnerContentIsRichText(): void
     {
diff --git a/tests/Unit/Integrations/Divi/Compose/VariableRefTest.php b/tests/Unit/Integrations/Divi/Compose/VariableRefTest.php
index 548412c..c351c94 100644
--- a/tests/Unit/Integrations/Divi/Compose/VariableRefTest.php
+++ b/tests/Unit/Integrations/Divi/Compose/VariableRefTest.php
@@ -134,6 +134,8 @@ final class VariableRefTest extends TestCase
                 '$variable({"type":"color","value":{"name":"gcid-a1b2;}</style><script>alert(1)</script>","settings":{}}})$',
                 'Name',
             ],
+            'settings on a global variable' => [self::content('gvid-s1', '{"before":"<b>x</b>"}'), 'before'],
+            'settings on a theme font' => [self::content('--et_global_heading_font', '{"after":""}'), 'after'],
             'unknown settings key' => [self::content('post_title', '{"before":"","foo":"1"}'), 'foo'],
             'setting the option lacks' => [self::content('post_featured_image', '{"before":"x"}'), 'before'],
             'enable_html' => [self::content('custom_meta_telefon', '{"before":"","after":"","enable_html":"on"}'), 'enable_html'],