--- a/browser/themes/osx/customizableui/panelUIOverlay.css
+++ b/browser/themes/osx/customizableui/panelUIOverlay.css
@@ -1,14 +1,18 @@
 /* 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/. */
 
 %include ../../shared/customizableui/panelUIOverlay.inc.css
 
+.panel-subviews {
+  background-color: hsla(0,0%,100%,.97);
+}
+
 @media (min-resolution: 2dppx) {
   #PanelUI-help[panel-multiview-anchor="true"]::after,
   toolbarbutton[panel-multiview-anchor="true"] {
     background-image: url(chrome://browser/skin/customizableui/subView-arrow-back-inverted@2x.png),
                       linear-gradient(rgba(255,255,255,0.3), rgba(255,255,255,0));
     background-size: 16px, auto;
   }
 

--- a/browser/themes/shared/customizableui/panelUIOverlay.inc.css
+++ b/browser/themes/shared/customizableui/panelUIOverlay.inc.css
@@ -96,22 +96,20 @@
 }
 
 #PanelUI-button:-moz-locale-dir(rtl) {
   background-position: 100% 0, calc(100% - 1px) 0, calc(100% - 2px) 0;
 }
 
 .panel-subviews {
   padding: 4px;
-  background-color: hsla(0,0%,100%,.97);
   background-clip: padding-box;
   border-left: 1px solid hsla(210,4%,10%,.3);
   box-shadow: 0 3px 5px hsla(210,4%,10%,.1),
               0 0 7px hsla(210,4%,10%,.1);
-  color: hsl(0,0%,15%);
   -moz-margin-start: @exitSubviewGutterWidth@;
 }
 
 .panel-viewstack[viewtype="main"] > .panel-subviews {
   transform: translateX(@menuPanelWidth@);
 }
 
 .panel-viewstack[viewtype="main"] > .panel-subviews:-moz-locale-dir(rtl) {

--- a/browser/themes/windows/customizableui/panelUIOverlay.css
+++ b/browser/themes/windows/customizableui/panelUIOverlay.css
@@ -1,14 +1,18 @@
 /* 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/. */
 
 %include ../../shared/customizableui/panelUIOverlay.inc.css
 
+.panel-subviews {
+  background-color: -moz-field;
+}
+
 #PanelUI-contents #zoom-out-btn {
   padding-left: 12px;
   padding-right: 12px;
 }
 
 #PanelUI-contents #zoom-in-btn {
   padding-left: 12px;
   padding-right: 12px;