diff -u b/core/themes/claro/claro.theme b/core/themes/claro/claro.theme
--- b/core/themes/claro/claro.theme
+++ b/core/themes/claro/claro.theme
@@ -1263,7 +1263,6 @@
  */
 function claro_form_media_library_add_form_upload_alter(array &$form, FormStateInterface $form_state) {
   $form['#attributes']['class'][] = 'media-library-add-form--upload';
-  $form['#attributes']['class'][] = 'form--small';
   if (isset($form['container']['upload'])) {
     // Set this flag so we can remove the details element.
     $form['container']['upload']['#do_not_wrap_in_details'] = TRUE;
@@ -1278,7 +1277,6 @@
  */
 function claro_form_media_library_add_form_oembed_alter(array &$form, FormStateInterface $form_state) {
   $form['#attributes']['class'][] = 'media-library-add-form--oembed';
-  $form['#attributes']['class'][] = 'form--small';
 
   // If no media items have been added yet, add a couple of styling classes
   // to the initial URL form.
@@ -1296,8 +1294,6 @@
  * they are saved.
  */
 function claro_preprocess_item_list__media_library_add_form_media_list(array &$variables) {
-  $variables['attributes']['class'][] = 'form--small';
-
   foreach ($variables['items'] as &$item) {
     $item['value']['preview']['#attributes']['class'][] = 'media-library-add-form__preview';
     $item['value']['fields']['#attributes']['class'][] = 'media-library-add-form__fields';