diff --git a/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/ckeditor/plugin/Internal.php b/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/ckeditor/plugin/Internal.php
index c1aaa9d..3a3ac28 100644
--- a/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/ckeditor/plugin/Internal.php
+++ b/core/modules/ckeditor/lib/Drupal/ckeditor/Plugin/ckeditor/plugin/Internal.php
@@ -52,7 +52,6 @@ public function getConfig(Editor $editor) {
     $config = array(
       'customConfig' => '', // Don't load CKEditor's config.js file.
       'pasteFromWordPromptCleanup' => TRUE,
-      'indentClasses' => array('indent1', 'indent2', 'indent3'),
       'justifyClasses' => array($rtl ? 'align-right' : 'align-left', 'align-center', $rtl ? 'align-left' : 'align-right', 'align-justify'),
       'coreStyles_underline' => array('element' => 'span', 'attributes' => array('class' => 'underline')),
       'removeDialogTabs' => 'image:Link;image:advanced;link:advanced',
diff --git a/core/modules/ckeditor/lib/Drupal/ckeditor/Tests/CKEditorTest.php b/core/modules/ckeditor/lib/Drupal/ckeditor/Tests/CKEditorTest.php
index 9181b59..b4d52ab 100644
--- a/core/modules/ckeditor/lib/Drupal/ckeditor/Tests/CKEditorTest.php
+++ b/core/modules/ckeditor/lib/Drupal/ckeditor/Tests/CKEditorTest.php
@@ -224,7 +224,6 @@ protected function getDefaultInternalConfig() {
     return array(
       'customConfig' => '',
       'pasteFromWordPromptCleanup' => TRUE,
-      'indentClasses' => array('indent1', 'indent2', 'indent3'),
       'justifyClasses' => array('align-left', 'align-center', 'align-right', 'align-justify'),
       'coreStyles_underline' => array('element' => 'span', 'attributes' => array('class' => 'underline')),
       'removeDialogTabs' => 'image:Link;image:advanced;link:advanced',
diff --git a/core/modules/system/system.base-rtl.css b/core/modules/system/system.base-rtl.css
index f404688..6e36c6c 100644
--- a/core/modules/system/system.base-rtl.css
+++ b/core/modules/system/system.base-rtl.css
@@ -68,15 +68,3 @@ div.tree-child-last {
 .align-justify {
   text-align: justify;
 }
-.indent1 {
-  margin-left: 0;
-  margin-right: 2em;
-}
-.indent2 {
-  margin-left: 0;
-  margin-right: 4em;
-}
-.indent3 {
-  margin-left: 0;
-  margin-right: 6em;
-}
diff --git a/core/modules/system/system.base.css b/core/modules/system/system.base.css
index 8cce19e..c40d552 100644
--- a/core/modules/system/system.base.css
+++ b/core/modules/system/system.base.css
@@ -289,18 +289,6 @@ input {
 .align-justify {
   text-align: justify;
 }
-.indent1 {
-  margin-left: 2em; /* LTR */
-  margin-right: 0; /* LTR */
-}
-.indent2 {
-  margin-left: 4em; /* LTR */
-  margin-right: 0; /* LTR */
-}
-.indent3 {
-  margin-left: 6em; /* LTR */
-  margin-right: 0; /* LTR */
-}
 .underline {
   text-decoration: underline;
 }