diff -u b/core/modules/node/css/node.admin.theme.css b/core/modules/node/css/node.admin.theme.css
--- b/core/modules/node/css/node.admin.theme.css
+++ b/core/modules/node/css/node.admin.theme.css
@@ -69,7 +69,7 @@
   }
 }
 
-/* Node preview container */
+/* Node preview container. */
 .node-preview-container {
   position: fixed;
   z-index: 499;
@@ -87,7 +87,7 @@
   }
 }
 
-/* Revision color */
+/* Revision color. */
 .revision-current {
   background: #ffc;
 }