diff --git a/themes/base/ui.tabs.css b/themes/base/ui.tabs.css
index e812426cb..db3b7708d 100644
--- a/themes/base/ui.tabs.css
+++ b/themes/base/ui.tabs.css
@@ -2,7 +2,7 @@
 ----------------------------------*/
 .ui-tabs { padding: .2em; zoom: 1; }
 .ui-tabs .ui-tabs-nav { padding: .2em .2em 0 .2em;  position: relative; }
-.ui-tabs .ui-tabs-nav li { float: left; border-bottom: 0 !important; margin: 0 .2em -1px 0; padding: 0; list-style: none; }
+.ui-tabs .ui-tabs-nav li { float: left; border-bottom-weight: 0 !important; margin: 0 .2em -1px 0; padding: 0; list-style: none; }
 .ui-tabs .ui-tabs-nav li a { float: left; display:block; text-decoration: none; padding: .5em 1em; }
 .ui-tabs .ui-tabs-nav li.ui-tabs-selected {  padding-bottom: .1em; border-bottom: 0; }
 .ui-tabs .ui-tabs-nav li.ui-tabs-selected a { cursor: text; }