diff --git a/misc/vertical-tabs.css b/misc/vertical-tabs.css
index d350c8e..40ad8ed 100644
--- a/misc/vertical-tabs.css
+++ b/misc/vertical-tabs.css
@@ -43,6 +43,9 @@ div.vertical-tabs {
 .vertical-tabs ul.vertical-tabs-list li a:hover strong {
   text-decoration: underline;
 }
+div.vertical-tabs ul li.vertical-tab-button:focus {
+  outline: 0;
+}
 .vertical-tabs ul.vertical-tabs-list li a:hover {
   outline: 1px dotted;
 }