diff --git a/wp-includes/class-wp-editor.php b/wp-includes/class-wp-editor.php
index 71236ba712..fb5c29be22 100644
--- a/wp-includes/class-wp-editor.php
+++ b/wp-includes/class-wp-editor.php
@@ -344,7 +344,7 @@ final class _WP_Editors {
 					'paste_strip_class_attributes' => 'all',
 					'paste_text_use_dialog' => true,
 					'webkit_fake_resize' => false,
-					'preview_styles' => 'font-family font-size font-weight text-decoration text-transform',
+					'preview_styles' => 'font-family font-weight text-decoration text-transform',
 					'spellchecker_rpc_url' => self::$baseurl . '/plugins/spellchecker/rpc.php',
 					'schema' => 'html5',
 					'wpeditimage_disable_captions' => $no_captions,
diff --git a/wp-includes/css/editor.css b/wp-includes/css/editor.css
index 0780b100a5..1728560879 100644
--- a/wp-includes/css/editor.css
+++ b/wp-includes/css/editor.css
@@ -586,7 +586,7 @@
 
 .wp_themeSkin .mce_h1 span.mceText {
 	font-weight: bolder;
-	font-size: 17px;
+	font-size: 18px;
 }
 
 .wp_themeSkin .mce_h2 span.mceText {
@@ -596,22 +596,22 @@
 
 .wp_themeSkin .mce_h3 span.mceText {
 	font-weight: bolder;
-	font-size: 15px;
+	font-size: 14px;
 }
 
 .wp_themeSkin .mce_h4 span.mceText {
 	font-weight: bolder;
-	font-size: 14px;
+	font-size: 12px;
 }
 
 .wp_themeSkin .mce_h5 span.mceText {
 	font-weight: bolder;
-	font-size: 13px;
+	font-size: 11px;
 }
 
 .wp_themeSkin .mce_h6 span.mceText {
 	font-weight: bolder;
-	font-size: 12px;
+	font-size: 10px;
 }
 
 /* Theme */