diff --git a/toolkit/themes/linux/global/global.css b/toolkit/themes/linux/global/global.css
index 5e13e993f976..2a2abdd0fc92 100644
--- a/toolkit/themes/linux/global/global.css
+++ b/toolkit/themes/linux/global/global.css
@@ -142,19 +142,6 @@ html|*#print-preview-pageNumber {
   text-shadow: 1px 1px 1.5px black;
 }
 
-.inset {
-  border: 1px solid ThreeDShadow;
-  border-right-color: ThreeDHighlight;
-  border-bottom-color: ThreeDHighlight;
-  margin: 0 5px 5px;
-}
-
-.outset {
-  border: 1px solid ThreeDShadow;
-  border-left-color: ThreeDHighlight;
-  border-top-color: ThreeDHighlight;
-}
-
 separator:not([orient="vertical"]) {
   height: 1.5em;
 }
diff --git a/toolkit/themes/osx/global/global.css b/toolkit/themes/osx/global/global.css
index 16b2a29b1a52..57a349c07f99 100644
--- a/toolkit/themes/osx/global/global.css
+++ b/toolkit/themes/osx/global/global.css
@@ -105,19 +105,6 @@ sidebarheader {
   text-shadow: 1px 1px 1.5px black;
 }
 
-.inset {
-  border: 1px solid ThreeDShadow;
-  border-right-color: ThreeDHighlight;
-  border-bottom-color: ThreeDHighlight;
-  margin: 0 5px 5px;
-}
-
-.outset {
-  border: 1px solid ThreeDShadow;
-  border-left-color: ThreeDHighlight;
-  border-top-color: ThreeDHighlight;
-}
-
 separator:not([orient="vertical"]) {
   height: 1.5em;
 }
diff --git a/toolkit/themes/windows/global/global.css b/toolkit/themes/windows/global/global.css
index a8d8a67c3d0c..84f3181949b6 100644
--- a/toolkit/themes/windows/global/global.css
+++ b/toolkit/themes/windows/global/global.css
@@ -143,19 +143,6 @@ html|*#print-preview-pageNumber {
   text-shadow: 1px 1px 1.5px black;
 }
 
-.inset {
-  border: 1px solid ThreeDShadow;
-  border-right-color: ThreeDHighlight;
-  border-bottom-color: ThreeDHighlight;
-  margin: 0 5px 5px;
-}
-
-.outset {
-  border: 1px solid ThreeDShadow;
-  border-left-color: ThreeDHighlight;
-  border-top-color: ThreeDHighlight;
-}
-
 /* separators */
 separator:not([orient="vertical"]) {
   height: 1.5em;