diff -r 000000000000 -r 6474c204b198 toolkit/themes/osx/global/tabbox.css
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/themes/osx/global/tabbox.css	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,150 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+    The default style of these tabs is that of an NSTabView with tabs at
+    the top in the "regular" size. These tabs can be used with or without
+    a tabbox element.
+    For bottom tabs you should use the "tabs-bottom" class on the tabbox
+    or the tabs element. Bottom tabs use a style that's similar to the
+    one used in Adium.
+*/
+
+@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
+
+tabbox {
+  margin: 0 5px;
+}
+
+tabpanels {
+  -moz-appearance: tabpanels;
+  padding: 33px 15px 15px;
+}
+
+tabs {
+  -moz-box-align: center;
+  font: menu;
+}
+
+tabbox > tabs {
+  padding: 0 10px;
+  margin-bottom: -12px;
+  position: relative;
+}
+
+tab {
+  -moz-appearance: tab;
+}
+
+tab:-moz-focusring {
+  /* Tab focus rings need to overlay adjacent tabs. */
+  position: relative;
+}
+
+tab:first-of-type {
+  -moz-padding-start: 2px;
+}
+
+tab:last-of-type {
+  -moz-padding-end: 2px;
+}
+
+@media (-moz-mac-lion-theme) {
+  tab[selected="true"] {
+    color: #FFF;
+    text-shadow: rgba(0, 0, 0, 0.4) 0 1px;
+  }
+}
+
+.tab-middle {
+  padding: 1px 6px 2px;
+}
+
+.tabs-left,
+.tabs-right  {
+  -moz-box-flex: 1;
+}
+
+/* Tabs at the bottom
+ * These tabs are smaller, left aligned and don't extend into the tabpanel.
+ */
+
+tabbox.tabs-bottom > tabpanels {
+  padding: 10px;
+}
+
+tabbox.tabs-bottom > tabs,
+tabs.tabs-bottom {
+  background-color: rgba(0, 0, 0, 0.1);
+  padding: 0;
+  margin: 0;
+  border-top: 2px solid;
+  -moz-border-top-colors: #888 rgba(0, 0, 0, 0.08);
+  -moz-box-align: start;
+  font: message-box;
+}
+
+tabbox.tabs-bottom > tabs > .tabs-left,
+tabs.tabs-bottom > .tabs-left {
+  -moz-box-flex: 0;
+}
+
+tabbox.tabs-bottom > tabs > tab,
+tabs.tabs-bottom > tab {
+  -moz-appearance: none;
+  margin: -1px 0 0;
+  padding: 0 0 2px 0;
+  position: relative;
+  -moz-border-end: 1px solid rgba(0, 0, 0, 0.19);
+}
+
+tabbox.tabs-bottom > tabs > tab > .tab-middle,
+tabs.tabs-bottom > tab > .tab-middle {
+  padding: 1px 2px 0 2px;
+}
+
+tabbox.tabs-bottom > tabs > tab:not([selected=true]):hover,
+tabs.tabs-bottom > tab:not([selected=true]):hover {
+  background-color: rgba(0, 0, 0, 0.1);
+  -moz-border-end-color: rgba(0, 0, 0, 0.1);
+}
+
+tabbox.tabs-bottom > tabs > tab[selected=true],
+tabs.tabs-bottom > tab[selected=true] {
+  color: #000;
+  text-shadow: none;
+  border: solid #888;
+  border-width: 0 2px 2px;
+  border-radius: 2px;
+  -moz-border-left-colors: rgba(0, 0, 0, 0.08) #888;
+  -moz-border-right-colors: rgba(0, 0, 0, 0.08) #888;
+  -moz-border-bottom-colors: rgba(0, 0, 0, 0.08) #888;
+  -moz-margin-end: -1px;
+  margin-top: -2px;
+  margin-bottom: 1px;
+  padding: 0;
+}
+
+tabbox.tabs-bottom > tabs > tab[beforeselected=true],
+tabs.tabs-bottom > tab[beforeselected=true] {
+  -moz-border-end-color: transparent;
+  -moz-margin-end: -2px;
+}
+
+tabbox.tabs-bottom > tabs > tab:first-of-type:not([selected=true]),
+tabs.tabs-bottom > tab:first-of-type:not([selected=true]) {
+  -moz-border-start: 4px solid transparent;
+}
+
+tabbox.tabs-bottom > tabs > tab:first-of-type[selected=true],
+tabs.tabs-bottom > tab:first-of-type[selected=true] {
+  -moz-margin-start: 2px;
+}
+
+tabbox.tabs-bottom,
+tabbox.tabs-bottom > tabpanels,
+tabbox.tabs-bottom > tabs > tab[selected=true] > .tab-middle,
+tabs.tabs-bottom > tab[selected=true] > .tab-middle {
+  -moz-appearance: dialog;
+}