diff --git a/doc/userguide/userguide.css b/doc/userguide/userguide.css
index f06df9215e..50ff0a57fe 100644
--- a/doc/userguide/userguide.css
+++ b/doc/userguide/userguide.css
@@ -14,6 +14,7 @@ body {
 
 .note {
   background-color: #ddeedd;
+  border: 1px solid #aaccaa;
   margin: 1em 0 1em 0;
   padding: 0.5em 1em 0.5em 1em;
   -moz-border-radius: 10px;