Index: src/wp-content/themes/twentyfourteen/css/blocks.css
===================================================================
--- src/wp-content/themes/twentyfourteen/css/blocks.css	(revision 60180)
+++ src/wp-content/themes/twentyfourteen/css/blocks.css	(working copy)
@@ -354,6 +354,10 @@
 .wp-block-latest-comments__comment,
 .wp-block-latest-comments__comment-excerpt,
 .wp-block-latest-comments__comment-excerpt p {
+	font-size: 1em;
+}
+
+.widget-area .wp-block-latest-comments {
 	font-size: 16px;
 }
 
Index: src/wp-content/themes/twentyfourteen/css/editor-blocks.css
===================================================================
--- src/wp-content/themes/twentyfourteen/css/editor-blocks.css	(revision 60180)
+++ src/wp-content/themes/twentyfourteen/css/editor-blocks.css	(working copy)
@@ -496,7 +496,7 @@
 .wp-block-latest-comments__comment,
 .wp-block-latest-comments__comment-excerpt,
 .wp-block-latest-comments__comment-excerpt p {
-	font-size: 16px;
+	font-size: 1em;
 }
 
 .editor-block-list__block .wp-block-latest-comments__comment-meta a,