Index: wp-content/themes/twentytwelve/rtl.css
===================================================================
--- wp-content/themes/twentytwelve/rtl.css	(revision 21427)
+++ wp-content/themes/twentytwelve/rtl.css	(working copy)
@@ -135,6 +135,10 @@
 	margin-right: 0.357142857rem;
 	margin-left: auto;
 }
+.commentlist .children {
+	margin-right: 48px;
+	margin-right: 3.428571429rem;
+}
 
 /* Comment form */
 #respond h3#reply-title #cancel-comment-reply-link {