diff --git a/core/modules/field_ui/css/field_ui.admin.css b/core/modules/field_ui/css/field_ui.admin.css
index cf59695..fc876bd 100644
--- a/core/modules/field_ui/css/field_ui.admin.css
+++ b/core/modules/field_ui/css/field_ui.admin.css
@@ -66,3 +66,12 @@
 .field-ui-overview .field-formatter-settings-edit-form .formatter-name{
   font-weight: bold;
 }
+
+/* Fieldset variant */
+fieldset.fieldset-no-border {
+  border: none;
+  padding: 0;
+}
+fieldset.fieldset-no-border legend {
+  text-transform: none;
+}
diff --git a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
index da092a7..a8471dc 100644
--- a/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
+++ b/core/modules/field_ui/lib/Drupal/field_ui/Form/FieldEditForm.php
@@ -89,15 +89,21 @@ public function buildForm(array $form, array &$form_state, FieldInstanceInterfac
 
     // Build the configurable field values.
     $cardinality = $field['cardinality'];
+
+    // Admin specific css.
+    $form['#attached']['css'][] = drupal_get_path('module', 'field_ui') . '/field_ui.admin.css';
+
     $form['field']['cardinality_container'] = array(
       // We can't use the container element because it doesn't support the title
       // or description properties.
-      '#type' => 'item',
       // Reset #parents to 'field', so the additional container does not appear.
       '#parents' => array('field'),
-      '#field_prefix' => '<div class="container-inline">',
-      '#field_suffix' => '</div>',
+      '#type' => 'fieldset',
       '#title' => t('Allowed number of values'),
+      '#attributes' => array('class' => array(
+        'container-inline',
+        'fieldset-no-border'
+      )),
     );
     $form['field']['cardinality_container']['cardinality'] = array(
       '#type' => 'select',