--- a/browser/themes/linux/preferences/in-content/dialog.css
+++ b/browser/themes/linux/preferences/in-content/dialog.css
@@ -1,19 +1,13 @@
 /* - 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/incontentprefs/dialog.inc.css
 
-label:not(.menu-text),
+label,
 textbox,
 description,
 .tab-text,
-caption label {
+menulist label {
   font-size: 1.11rem;
 }
-
-/* Create a separate rule to unset these styles on .tree-input instead of
-   using :not(.tree-input) so the selector specifity doesn't change. */
-textbox.tree-input {
-  font-size: unset;
-}

--- a/browser/themes/linux/preferences/in-content/preferences.css
+++ b/browser/themes/linux/preferences/in-content/preferences.css
@@ -5,17 +5,17 @@
 %include ../../../shared/incontentprefs/preferences.inc.css
 
 html *,
 page *,
 window * {
   font-size: 1.11rem;
 }
 
-caption label:not(.dialogTitle) {
+caption label {
   font-size: 1.27rem;
 }
 
 .tip-caption,
 .help-label {
   font-size: 1rem;
 }
 

--- a/browser/themes/osx/preferences/in-content/dialog.css
+++ b/browser/themes/osx/preferences/in-content/dialog.css
@@ -4,29 +4,23 @@
 
 %include ../../../shared/incontentprefs/dialog.inc.css
 
 prefwindow,
 .windowDialog {
   font: message-box !important;
 }
 
-label:not(.menu-text),
+label,
 textbox,
 description,
 .tab-text,
-caption label {
+menulist label {
   font-size: 1.36rem;
 }
 
-/* Create a separate rule to unset these styles on .tree-input instead of
-   using :not(.tree-input) so the selector specifity doesn't change. */
-textbox.tree-input {
-  font-size: unset;
-}
-
 caption {
   font: message-box;
 }
 
 .prefWindow-dlgbuttons {
   margin: 0;
 }

--- a/browser/themes/osx/preferences/in-content/preferences.css
+++ b/browser/themes/osx/preferences/in-content/preferences.css
@@ -5,17 +5,17 @@
 %include ../../../shared/incontentprefs/preferences.inc.css
 
 html *,
 page *,
 window * {
   font-size: 1.36rem;
 }
 
-caption label:not(.dialogTitle) {
+caption label {
   font-size: 1.55rem;
 }
 
 .tip-caption,
 .help-label {
   font-size: 1.18rem;
 }
 

--- a/browser/themes/shared/incontentprefs/dialog.inc.css
+++ b/browser/themes/shared/incontentprefs/dialog.inc.css
@@ -61,8 +61,17 @@ groupbox {
 prefpane .groupbox-body {
   padding: 0 0 5px;
 }
 
 groupbox description {
   margin-right: 0;
   margin-left: 0;
 }
+
+label.menu-text,
+textbox.tree-input {
+  font-size: unset;
+}
+
+menulist label {
+  font-weight: unset;
+}

--- a/browser/themes/shared/incontentprefs/preferences.inc.css
+++ b/browser/themes/shared/incontentprefs/preferences.inc.css
@@ -415,16 +415,17 @@ button > hbox > label {
 .dialogBox > .groupbox-title {
   margin-top: 0;
   padding: 3.5px 0;
   background-color: #F1F1F1;
   border-bottom: 1px solid #C1C1C1;
 }
 
 .dialogTitle {
+  font-size: unset;
   text-align: center;
   -moz-user-select: none;
 }
 
 .close-icon {
   border: none;
   background: none !important;
   min-width: 0;

--- a/browser/themes/windows/preferences/in-content/dialog.css
+++ b/browser/themes/windows/preferences/in-content/dialog.css
@@ -1,19 +1,13 @@
 /* - 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/incontentprefs/dialog.inc.css
 
-label:not(.menu-text),
+label,
 textbox,
 description,
 .tab-text,
-caption label {
+menulist label {
   font-size: 1.25rem;
 }
-
-/* Create a separate rule to unset these styles on .tree-input instead of
-   using :not(.tree-input) so the selector specifity doesn't change. */
-textbox.tree-input {
-  font-size: unset;
-}

--- a/browser/themes/windows/preferences/in-content/preferences.css
+++ b/browser/themes/windows/preferences/in-content/preferences.css
@@ -5,17 +5,17 @@
 %include ../../../shared/incontentprefs/preferences.inc.css
 
 html *,
 page *,
 window * {
   font-size: 1.25rem;
 }
 
-caption label:not(.dialogTitle) {
+caption label {
   font-size: 1.42rem;
 }
 
 .tip-caption,
 .help-label {
   font-size: 1.08rem;
 }