Feature: adds a css class for the form design (#7665)

src/DonationForms/ViewModels/DonationFormViewModel.php

@@ -252,6 +252,7 @@ public function exports(): array
      * 5. Finally, call the specific WP function wp_print_footer_scripts()
      *  - This will only print the footer scripts that are enqueued within our route.
      *
+     * @unreleased Adds class for form design
      * @since 3.11.0 Sanitize customCSS property
      * @since 3.0.0
      */
@@ -277,7 +278,7 @@ public function render(): string
         endif; ?>
 
         <?php
-        $classNames = ['givewp-donation-form'];
+        $classNames = ['givewp-donation-form', "givewp-donation-form-design--{$this->designId()}"];
 
         if ($this->previewMode) {
             $classNames[] = 'givewp-donation-form--preview';