--- a/toolkit/themes/linux/global/in-content/common.css
+++ b/toolkit/themes/linux/global/in-content/common.css
@@ -1,13 +1,16 @@
 /* - 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/in-content/common.inc.css
+@import url("chrome://global/skin/in-content/common-shared.css");
+
+@namespace html "http://www.w3.org/1999/xhtml";
+@namespace xul "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 @media (prefers-color-scheme: dark) {
   /* Don't apply scrollbar-color since it removes the native scrollbar style on Linux */
   :root {
     scrollbar-color: initial;
   }
 }
 

--- a/toolkit/themes/linux/global/jar.mn
+++ b/toolkit/themes/linux/global/jar.mn
@@ -19,9 +19,9 @@ toolkit.jar:
    skin/classic/global/splitter.css
    skin/classic/global/tabbox.css
    skin/classic/global/toolbar.css
    skin/classic/global/toolbarbutton.css
    skin/classic/global/tooltip.css
 
    skin/classic/global/icons/Authentication.png                (icons/Authentication.png)
 
-*  skin/classic/global/in-content/common.css                   (in-content/common.css)
+   skin/classic/global/in-content/common.css                   (in-content/common.css)

--- a/toolkit/themes/osx/global/in-content/common.css
+++ b/toolkit/themes/osx/global/in-content/common.css
@@ -1,13 +1,16 @@
 /* - 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/in-content/common.inc.css
+@import url("chrome://global/skin/in-content/common-shared.css");
+
+@namespace html "http://www.w3.org/1999/xhtml";
+@namespace xul "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 xul|tabs {
   padding-inline: 0;
   position: static;
 }
 
 xul|button[dlgtype="help"] {
   appearance: none;

--- a/toolkit/themes/osx/global/jar.mn
+++ b/toolkit/themes/osx/global/jar.mn
@@ -25,9 +25,9 @@ toolkit.jar:
   skin/classic/global/tooltip.css
   skin/classic/global/wizard.css
   skin/classic/global/arrow/panelarrow-vertical.svg                  (arrow/panelarrow-vertical.svg)
   skin/classic/global/icons/search-textbox.svg                       (icons/search-textbox.svg)
   skin/classic/global/icons/warning-64.png                           (icons/warning-64.png)
   skin/classic/global/icons/warning-large.png                        (icons/warning-large.png)
   skin/classic/global/icons/error-64.png                             (icons/error-64.png)
   skin/classic/global/icons/question-64.png                          (icons/question-64.png)
-* skin/classic/global/in-content/common.css                          (in-content/common.css)
+  skin/classic/global/in-content/common.css                          (in-content/common.css)

--- a/toolkit/themes/shared/desktop-jar.inc.mn
+++ b/toolkit/themes/shared/desktop-jar.inc.mn
@@ -36,16 +36,17 @@
   skin/classic/global/dirListing/dirListing.css            (../../shared/dirListing/dirListing.css)
 #ifdef XP_MACOSX
   skin/classic/global/dirListing/folder.png                (../../shared/dirListing/folder-osx.png)
   skin/classic/global/dirListing/up.png                    (../../shared/dirListing/up-osx.png)
 #else
   skin/classic/global/dirListing/folder.png                (../../shared/dirListing/folder.png)
   skin/classic/global/dirListing/up.png                    (../../shared/dirListing/up.png)
 #endif
+  skin/classic/global/in-content/common-shared.css         (../../shared/in-content/common-shared.css)
   skin/classic/global/in-content/info-pages.css            (../../shared/in-content/info-pages.css)
   skin/classic/global/in-content/toggle-button.css         (../../shared/in-content/toggle-button.css)
   skin/classic/global/icons/arrow-left.svg                 (../../shared/icons/arrow-left.svg)
   skin/classic/global/icons/arrow-right.svg                (../../shared/icons/arrow-right.svg)
   skin/classic/global/icons/autoscroll.svg                 (../../shared/icons/autoscroll.svg)
   skin/classic/global/icons/autoscroll-horizontal.svg      (../../shared/icons/autoscroll-horizontal.svg)
   skin/classic/global/icons/autoscroll-vertical.svg        (../../shared/icons/autoscroll-vertical.svg)
   skin/classic/global/icons/badge-blue.svg                 (../../shared/icons/badge-blue.svg)

rename from toolkit/themes/shared/in-content/common.inc.css
rename to toolkit/themes/shared/in-content/common-shared.css

--- a/toolkit/themes/windows/global/in-content/common.css
+++ b/toolkit/themes/windows/global/in-content/common.css
@@ -1,13 +1,16 @@
 /* - 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/in-content/common.inc.css
+@import url("chrome://global/skin/in-content/common-shared.css");
+
+@namespace html "http://www.w3.org/1999/xhtml";
+@namespace xul "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 
 xul|menulist::part(dropmarker) {
   margin-block: 1px;
 }
 
 xul|checkbox,
 xul|radio {
   padding-inline-start: 0;

--- a/toolkit/themes/windows/global/jar.mn
+++ b/toolkit/themes/windows/global/jar.mn
@@ -22,11 +22,11 @@ toolkit.jar:
   skin/classic/global/toolbar.css
   skin/classic/global/toolbarbutton.css
   skin/classic/global/tooltip.css
   skin/classic/global/icons/Landscape.png                  (icons/Landscape.png)
   skin/classic/global/icons/menu-check.svg                 (icons/menu-check.svg)
   skin/classic/global/icons/Portrait.png                   (icons/Portrait.png)
   skin/classic/global/icons/Print-preview.png              (icons/Print-preview.png)
   skin/classic/global/icons/warning-large.png              (icons/warning-large.png)
-* skin/classic/global/in-content/common.css                (in-content/common.css)
+  skin/classic/global/in-content/common.css                (in-content/common.css)
   skin/classic/global/tree/sort-asc.svg                    (tree/sort-asc.svg)
   skin/classic/global/tree/sort-dsc.svg                    (tree/sort-dsc.svg)