diff --git a/mail/base/content/systemIntegrationDialog.xhtml b/mail/base/content/systemIntegrationDialog.xhtml
index 0affe4a093..81c5d2b7f5 100644
--- a/mail/base/content/systemIntegrationDialog.xhtml
+++ b/mail/base/content/systemIntegrationDialog.xhtml
@@ -10,7 +10,8 @@
 <window xmlns:html="http://www.w3.org/1999/xhtml"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         onload="gSystemIntegrationDialog.onLoad();"
-        data-l10n-id="system-integration-title">
+        data-l10n-id="system-integration-title"
+        style="min-width: 33em;">
 <dialog id="systemIntegrationDialog"
         buttons="accept,cancel"
         data-l10n-id="system-integration-dialog"
diff --git a/mail/components/preferences/applicationManager.xhtml b/mail/components/preferences/applicationManager.xhtml
index 013992a54a..6e3fb13bc6 100644
--- a/mail/components/preferences/applicationManager.xhtml
+++ b/mail/components/preferences/applicationManager.xhtml
@@ -13,7 +13,7 @@
         xmlns:html="http://www.w3.org/1999/xhtml"
         onload="gAppManagerDialog.init();"
         data-l10n-id="app-manager-window-dialog"
-        data-l10n-attrs="style">
+        style="min-width: 30em;">
 <dialog id="appManager"
         buttons="accept,cancel">
 
diff --git a/mail/components/preferences/attachmentReminder.xhtml b/mail/components/preferences/attachmentReminder.xhtml
index 2ca7b939cf..cbe1bb7a14 100644
--- a/mail/components/preferences/attachmentReminder.xhtml
+++ b/mail/components/preferences/attachmentReminder.xhtml
@@ -12,7 +12,7 @@
         xmlns:html="http://www.w3.org/1999/xhtml"
         data-l10n-id="attachment-reminder-window"
         onload="gAttachmentReminderOptionsDialog.init();"
-        style="width:38em;">
+        style="min-width: 38em;">
   <dialog id="attachmentReminderOptionsDialog"
           dlgbuttons="accept,cancel">
     <script src="chrome://messenger/content/preferences/attachmentReminder.js"/>
diff --git a/mail/components/preferences/colors.xhtml b/mail/components/preferences/colors.xhtml
index 1cb170c0a2..1800d0999a 100644
--- a/mail/components/preferences/colors.xhtml
+++ b/mail/components/preferences/colors.xhtml
@@ -10,8 +10,7 @@
 <window type="child"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         xmlns:html="http://www.w3.org/1999/xhtml"
-        data-l10n-id="colors-dialog-window"
-        data-l10n-attrs="style">
+        data-l10n-id="colors-dialog-window">
   <dialog id="ColorsDialog"
           dlgbuttons="accept,cancel">
 
diff --git a/mail/components/preferences/connection.xhtml b/mail/components/preferences/connection.xhtml
index f010dfd6b7..ae7ebe75fe 100644
--- a/mail/components/preferences/connection.xhtml
+++ b/mail/components/preferences/connection.xhtml
@@ -12,7 +12,7 @@
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         xmlns:html="http://www.w3.org/1999/xhtml"
         data-l10n-id="connection-dialog-window"
-        data-l10n-attrs="style"
+        style="min-width: 49em;"
         onload="gConnectionsDialog.checkForSystemProxy();">
 <dialog id="ConnectionsDialog"
         dlgbuttons="accept,cancel">
diff --git a/mail/components/preferences/cookies.xhtml b/mail/components/preferences/cookies.xhtml
index 7e1d3b96e4..7bc7253c10 100644
--- a/mail/components/preferences/cookies.xhtml
+++ b/mail/components/preferences/cookies.xhtml
@@ -13,7 +13,6 @@
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         xmlns:html="http://www.w3.org/1999/xhtml"
         data-l10n-id="cookies-window-dialog"
-        data-l10n-attrs="style"
         onload="gCookiesWindow.init();"
         onunload="gCookiesWindow.uninit();"
         persist="width height">
diff --git a/mail/components/preferences/dockoptions.xhtml b/mail/components/preferences/dockoptions.xhtml
index b767608946..fff473d2e9 100644
--- a/mail/components/preferences/dockoptions.xhtml
+++ b/mail/components/preferences/dockoptions.xhtml
@@ -11,7 +11,7 @@
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         xmlns:html="http://www.w3.org/1999/xhtml"
         data-l10n-id="dock-options-window-dialog"
-        data-l10n-attrs="style">
+        style="min-width: 33em;">
   <dialog id="DockOptionsDialog"
           dlgbuttons="accept,cancel">
 
diff --git a/mail/components/preferences/messengerLanguages.xhtml b/mail/components/preferences/messengerLanguages.xhtml
index 28ae4851ba..f44ee46cbb 100644
--- a/mail/components/preferences/messengerLanguages.xhtml
+++ b/mail/components/preferences/messengerLanguages.xhtml
@@ -10,7 +10,6 @@
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         xmlns:html="http://www.w3.org/1999/xhtml"
         data-l10n-id="messenger-languages-window"
-        data-l10n-attrs="title, style"
         onload="gMessengerLanguagesDialog.onLoad();">
 <dialog id="MessengerLanguagesDialog"
         buttons="accept,cancel">
diff --git a/mail/components/preferences/passwordManager.xhtml b/mail/components/preferences/passwordManager.xhtml
index cfaa63f0ce..231b1b085e 100644
--- a/mail/components/preferences/passwordManager.xhtml
+++ b/mail/components/preferences/passwordManager.xhtml
@@ -12,7 +12,6 @@
         onload="Startup();"
         onunload="Shutdown();"
         data-l10n-id="saved-logins"
-        style="width: 45em;"
         persist="width height">
 
   <linkset>
diff --git a/mail/components/preferences/permissions.xhtml b/mail/components/preferences/permissions.xhtml
index 60e1753469..074a0a9f9c 100644
--- a/mail/components/preferences/permissions.xhtml
+++ b/mail/components/preferences/permissions.xhtml
@@ -11,7 +11,6 @@
 
 <window id="PermissionsDialog" class="windowDialog"
         data-l10n-id="permissions-reminder-window"
-        data-l10n-attrs="style"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         xmlns:html="http://www.w3.org/1999/xhtml"
         onload="gPermissionManager.onLoad();"
diff --git a/mail/extensions/openpgp/content/ui/keyWizard.xhtml b/mail/extensions/openpgp/content/ui/keyWizard.xhtml
index 43fc9c8b7a..68968d5215 100644
--- a/mail/extensions/openpgp/content/ui/keyWizard.xhtml
+++ b/mail/extensions/openpgp/content/ui/keyWizard.xhtml
@@ -16,7 +16,7 @@
         xmlns:html="http://www.w3.org/1999/xhtml"
         onload="init();"
         lightweightthemes="true"
-        style="width: 50em;">
+        style="min-width: 50em;">
 <dialog id="openPgpKeyWizardDialog"
         data-l10n-id="key-wizard-dialog"
         data-l10n-attrs="buttonlabelaccept,buttonlabelextra1"
diff --git a/mail/locales/en-US/messenger/preferences/application-manager.ftl b/mail/locales/en-US/messenger/preferences/application-manager.ftl
index 7c813af0dd..7d1cad78c6 100644
--- a/mail/locales/en-US/messenger/preferences/application-manager.ftl
+++ b/mail/locales/en-US/messenger/preferences/application-manager.ftl
@@ -4,7 +4,6 @@
 
 app-manager-window-dialog =
     .title = Application Details
-    .style = width: 30em; min-height: 20em;
 
 remove-app-button =
     .label = Remove
diff --git a/mail/locales/en-US/messenger/preferences/colors.ftl b/mail/locales/en-US/messenger/preferences/colors.ftl
index e6ea5998b1..ddfa41c52c 100644
--- a/mail/locales/en-US/messenger/preferences/colors.ftl
+++ b/mail/locales/en-US/messenger/preferences/colors.ftl
@@ -4,10 +4,6 @@
 
 colors-dialog-window =
     .title = Colors
-    .style = { PLATFORM() ->
-        [macos] width: 41em !important
-        *[other] width: 38em !important
-    }
 
 colors-dialog-legend = Text and Background
 
diff --git a/mail/locales/en-US/messenger/preferences/connection.ftl b/mail/locales/en-US/messenger/preferences/connection.ftl
index b85d4ea40e..4e35b2a358 100644
--- a/mail/locales/en-US/messenger/preferences/connection.ftl
+++ b/mail/locales/en-US/messenger/preferences/connection.ftl
@@ -20,10 +20,6 @@ connection-dns-over-https-custom-label = Custom
 
 connection-dialog-window =
     .title = Connection Settings
-    .style = { PLATFORM() ->
-        [macos] width: 44em !important
-        *[other] width: 49em !important
-    }
 
 disable-extension-button = Disable Extension
 
diff --git a/mail/locales/en-US/messenger/preferences/cookies.ftl b/mail/locales/en-US/messenger/preferences/cookies.ftl
index 8eacbdad84..b95afaacfe 100644
--- a/mail/locales/en-US/messenger/preferences/cookies.ftl
+++ b/mail/locales/en-US/messenger/preferences/cookies.ftl
@@ -4,7 +4,6 @@
 
 cookies-window-dialog =
     .title = Cookies
-    .style = width: 36em;
 
 window-close-key =
     .key = w
diff --git a/mail/locales/en-US/messenger/preferences/dock-options.ftl b/mail/locales/en-US/messenger/preferences/dock-options.ftl
index d0dbeb8584..be0062ec90 100644
--- a/mail/locales/en-US/messenger/preferences/dock-options.ftl
+++ b/mail/locales/en-US/messenger/preferences/dock-options.ftl
@@ -4,7 +4,6 @@
 
 dock-options-window-dialog =
     .title = App icon options
-    .style = width: 35em;
 
 dock-options-show-badge =
     .label = Show badge icon
diff --git a/mail/locales/en-US/messenger/preferences/languages.ftl b/mail/locales/en-US/messenger/preferences/languages.ftl
index ecdb69e844..21426595f9 100644
--- a/mail/locales/en-US/messenger/preferences/languages.ftl
+++ b/mail/locales/en-US/messenger/preferences/languages.ftl
@@ -23,7 +23,6 @@ languages-customize-add =
 
 messenger-languages-window =
     .title = { -brand-short-name } Language Settings
-    .style = width: 40em
 
 messenger-languages-description = { -brand-short-name } will display the first language as your default and will display alternate languages if necessary in the order they appear.
 
diff --git a/mail/locales/en-US/messenger/preferences/permissions.ftl b/mail/locales/en-US/messenger/preferences/permissions.ftl
index 920a64e99f..55c97b6031 100644
--- a/mail/locales/en-US/messenger/preferences/permissions.ftl
+++ b/mail/locales/en-US/messenger/preferences/permissions.ftl
@@ -4,7 +4,6 @@
 
 permissions-reminder-window =
     .title = Exceptions
-    .style = width: 45em;
 
 permission-preferences-close-window =
     .key = w
diff --git a/mail/themes/shared/mail/preferences/subdialog.css b/mail/themes/shared/mail/preferences/subdialog.css
index 72b2b2a2c5..94cb0aa102 100644
--- a/mail/themes/shared/mail/preferences/subdialog.css
+++ b/mail/themes/shared/mail/preferences/subdialog.css
@@ -69,7 +69,7 @@ xul|window > :is(xul|dialog, xul|hbox, xul|vbox) {
   -moz-box-flex: 1;
   /* Default dialog dimensions */
   height: 12em;
-  width: 40ch;
+  min-width: 40ch;
 }
 
 .largeDialogContainer.doScroll {