diff --git a/metatag.inc b/metatag.inc
index 2f62352..1fd2ea2 100644
--- a/metatag.inc
+++ b/metatag.inc
@@ -203,6 +203,9 @@ class DrupalTextMetaTag extends DrupalDefaultMetaTag {
       '#element_validate' => array('token_element_validate'),
       '#token_types' => $options['token types'],
       '#maxlength' => 1024,
+      // Make the field name safe for use in CSS.
+      // @see theme_form_element().
+      '#name' => strtr($this->info['name'], array('.' => '-', ':' => '-')),
     );
 
     // Optional handling for items that allow multiple values.
diff --git a/metatag.module b/metatag.module
index cd3cfa4..fe0f3fd 100644
--- a/metatag.module
+++ b/metatag.module
@@ -1349,6 +1349,9 @@ function metatag_metatags_form(array &$form, $instance, array $metatags = array(
           '#description' => !empty($group['description']) ? t($group['description']) : '',
           '#collapsible' => TRUE,
           '#collapsed' => TRUE,
+          // Make the field name safe for use in CSS.
+          // @see theme_form_element().
+          '#name' => strtr($metatag, array('.' => '-', ':' => '-')),
         );
       }
       $form['metatags'][$langcode][$group_key][$metatag] = $metatag_form + array('#parents' => array('metatags', $langcode, $metatag));