diff --git a/css/leptonChrome.css b/css/leptonChrome.css
index 6e59800..d9c032d 100644
--- a/css/leptonChrome.css
+++ b/css/leptonChrome.css
@@ -3176,7 +3176,8 @@
 @supports -moz-bool-pref("userChrome.rounding.square_menuitem") {
   xul|menulist:not([native]),
   xul|menulist > xul|menupopup xul|menu,
-  xul|menulist > xul|menupopup xul|menuitem {
+  xul|menulist > xul|menupopup xul|menuitem,
+  .customization-uidensity-menuitem {
     border-radius: 0 !important;
   }
 }
diff --git a/css/leptonContent.css b/css/leptonContent.css
index 1f33559..6663c0f 100644
--- a/css/leptonContent.css
+++ b/css/leptonContent.css
@@ -2787,12 +2787,14 @@
 }
 /** Rounding ******************************************************************/
 @supports -moz-bool-pref("userChrome.rounding.square_button") {
-  @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/"), url-prefix("chrome://pippki/content/")
+  @-moz-document url-prefix("about:"), regexp("^chrome://\\w+/content/.*.xhtml$")
   {
     button,
     .close-icon,
     .action-icon::before,
     .web-appearance-choice,
+    .page-section-header > .twisty,
+    .closed-tab-li-main,
     #categories > .category,
     .sidebar-footer-link {
       border-radius: 0 !important;
@@ -2847,7 +2849,7 @@
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_checklabel") {
-  @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/"), url-prefix("chrome://pippki/content/")
+  @-moz-document url-prefix("about:"), regexp("^chrome://\\w+/content/.*.xhtml$")
   {
     input[type="checkbox"]:not(.toggle-button),
     .checkbox-check {
@@ -2856,7 +2858,7 @@
   }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_field") {
-  @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/"), url-prefix("chrome://pippki/content/")
+  @-moz-document url-prefix("about:"), regexp("^chrome://\\w+/content/.*.xhtml$")
   {
     input:is([type="color"], [type="email"], [type="tel"], [type="text"], [type="password"], [type="url"], [type="number"]),
     textarea,
diff --git a/src/contents/_rounding.scss b/src/contents/_rounding.scss
index fb5fff7..b0452d1 100644
--- a/src/contents/_rounding.scss
+++ b/src/contents/_rounding.scss
@@ -1,13 +1,14 @@
 @include Option("userChrome.rounding.square_button") {
   @include moz-document(
     url-prefix "about:",
-    url-prefix "chrome://browser/content/",
-    url-prefix "chrome://pippki/content/"
+    regexp "^chrome:\/\/\\w+\/content\/.*\.xhtml$"
   ) {
     button,
     .close-icon,
     .action-icon::before,
     .web-appearance-choice,
+    .page-section-header > .twisty,
+    .closed-tab-li-main,
     #categories > .category,
     .sidebar-footer-link {
       border-radius: 0 !important;
@@ -71,8 +72,7 @@
 @include Option("userChrome.rounding.square_checklabel") {
   @include moz-document(
     url-prefix "about:",
-    url-prefix "chrome://browser/content/",
-    url-prefix "chrome://pippki/content/"
+    regexp "^chrome:\/\/\\w+\/content\/.*\.xhtml$"
   ) {
     input[type="checkbox"]:not(.toggle-button),
     .checkbox-check {
@@ -84,8 +84,7 @@
 @include Option("userChrome.rounding.square_field") {
   @include moz-document(
     url-prefix "about:",
-    url-prefix "chrome://browser/content/",
-    url-prefix "chrome://pippki/content/"
+    regexp "^chrome:\/\/\\w+\/content\/.*\.xhtml$"
   ) {
     input:is([type="color"], [type="email"], [type="tel"], [type="text"], [type="password"], [type="url"], [type="number"]),
     textarea,
diff --git a/src/rounding/_square.scss b/src/rounding/_square.scss
index f978e11..6411f61 100644
--- a/src/rounding/_square.scss
+++ b/src/rounding/_square.scss
@@ -65,7 +65,8 @@
 @include Option("userChrome.rounding.square_menuitem") {
   xul|menulist:not([native]),
   xul|menulist > xul|menupopup xul|menu,
-  xul|menulist > xul|menupopup xul|menuitem {
+  xul|menulist > xul|menupopup xul|menuitem,
+  .customization-uidensity-menuitem {
     border-radius: 0 !important;
   }
 }