--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -5,18 +5,16 @@
 %endif
 
 @import url("chrome://global/skin/");
 
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 @namespace html url("http://www.w3.org/1999/xhtml");
 @namespace svg url("http://www.w3.org/2000/svg");
 
-%include ../shared/browser.inc
-
 %include ../shared/browser.inc.css
 
 :root {
   --tabs-border: rgba(0,0,0,.3);
 
   --toolbar-non-lwt-bgcolor: -moz-dialog;
   --toolbar-non-lwt-textcolor: -moz-dialogtext;
   --toolbar-non-lwt-bgimage: linear-gradient(rgba(255,255,255,.15), rgba(255,255,255,.15));

--- a/browser/themes/osx/shared.inc
+++ b/browser/themes/osx/shared.inc
@@ -1,7 +1,6 @@
 %include ../../../toolkit/themes/osx/global/shared.inc
-%include ../shared/browser.inc
 
 %filter substitution
 
 %define hudButton -moz-appearance: none; color: #434343; border-radius: 4px; border: 1px solid #b5b5b5; background: linear-gradient(#fff, #f2f2f2); box-shadow: inset 0 1px rgba(255,255,255,.8), inset 0 0 1px rgba(255,255, 255,.25), 0 1px rgba(255,255,255,.3); background-clip: padding-box; background-origin: padding-box; padding: 2px 6px;
 %define hudButtonPressed box-shadow: inset 0 1px 4px -3px #000, 0 1px rgba(255,255,255,.3);

deleted file mode 100644
--- a/browser/themes/shared/browser.inc
+++ /dev/null
@@ -1,8 +0,0 @@
-%filter substitution
-
-% Note that zoom-reset-button is a bit different since it doesn't use an image and thus has the image with display: none.
-%define nestedButtons #zoom-out-button, #zoom-reset-button, #zoom-in-button, #cut-button, #copy-button, #paste-button
-
-%define inAnyPanel :-moz-any(:not([cui-areatype="toolbar"]), [overflowedItem=true])
-
-%define panelPaletteIconSize var(--panel-palette-icon-size)
\ No newline at end of file

--- a/browser/themes/shared/customizableui/panelUI.inc.css
+++ b/browser/themes/shared/customizableui/panelUI.inc.css
@@ -12,26 +12,25 @@
 % There's no calc() here (and therefore lots of calc() where this is used) because
 % we don't support nested calc(): https://bugzilla.mozilla.org/show_bug.cgi?id=968761
 %define menuPanelButtonWidth (@menuPanelWidth@ / 3 - 0.1px)
 %define buttonStateHover :not(:-moz-any([disabled],[open],:active)):-moz-any(:hover,:focus)
 %define menuStateHover :not(:-moz-any([disabled],:active))[_moz-menuactive]
 %define buttonStateActive :not([disabled]):-moz-any([open],:hover:active)
 %define menuStateActive :not([disabled])[_moz-menuactive]:active
 %define menuStateMenuActive :not([disabled])[_moz-menuactive]
-
-%include ../browser.inc
+%define inAnyPanel :-moz-any(:not([cui-areatype="toolbar"]), [overflowedItem=true])
+%define panelPaletteIconSize 16px
 
 :root {
   --panel-ui-exit-subview-gutter-width: 38px;
   --appmenu-yellow-warning-border-color: hsl(45, 100%, 77%);
   --appmenu-yellow-warning-color: #FFEFBF;
   --appmenu-yellow-warning-hover-color: #FFE8A2;
   --appmenu-yellow-warning-active-color: #FFE38F;
-  --panel-palette-icon-size: 16px;
 }
 
 #PanelUI-popup #PanelUI-contents:empty {
   height: 128px;
 }
 
 #PanelUI-popup #PanelUI-contents:empty::before {
   content: "";

--- a/browser/themes/windows/browser-aero.css
+++ b/browser/themes/windows/browser-aero.css
@@ -1,12 +1,14 @@
 /* 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/. */
 
+%filter substitution
+%define toolbarShadowColor hsla(209,67%,12%,0.35)
 %define glassActiveBorderColor rgb(37, 44, 51)
 %define glassInactiveBorderColor rgb(102, 102, 102)
 
 @media not all and (-moz-windows-classic) {
   #main-window[sizemode="normal"] > #tab-view-deck > #browser-panel > #navigator-toolbox > #toolbar-menubar {
     margin-top: 1px;
   }
 }

--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -3,19 +3,16 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 @import url("chrome://global/skin/");
 
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 @namespace html url("http://www.w3.org/1999/xhtml");
 @namespace svg url("http://www.w3.org/2000/svg");
 
-%include ../shared/browser.inc
-%define toolbarShadowColor hsla(209,67%,12%,0.35)
-
 %include ../shared/browser.inc.css
 
 :root {
   --titlebar-text-color: currentColor;
 
   --tabs-border: threedshadow;
 
   --toolbar-non-lwt-bgcolor: -moz-dialog;