diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index ed7c82a2dd..4833bd405f 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -1512,11 +1512,13 @@ headerbar {
 
   .solid-csd & {
     &:backdrop, & {
-      margin-left: -1px;
-      margin-right: -1px;
-      margin-top: -1px;
-      border-radius: 0;
-      box-shadow: none;
+      &:dir(rtl), &:dir(ltr) { // specificity bump
+        margin-left: -1px;
+        margin-right: -1px;
+        margin-top: -1px;
+        border-radius: 0;
+        box-shadow: none;
+      }
     }
   }
 }
diff --git a/gtk/theme/Adwaita/gtk-contained-dark.css b/gtk/theme/Adwaita/gtk-contained-dark.css
index e159f508d8..4e647dbd36 100644
--- a/gtk/theme/Adwaita/gtk-contained-dark.css
+++ b/gtk/theme/Adwaita/gtk-contained-dark.css
@@ -1929,9 +1929,11 @@ headerbar {
       min-width: 26px;
       margin: 0;
       padding: 0; }
-  .solid-csd .titlebar:backdrop:not(headerbar), .solid-csd .titlebar:not(headerbar), .solid-csd
-  headerbar:backdrop, .solid-csd
-  headerbar {
+  .solid-csd .titlebar:backdrop:dir(rtl):not(headerbar), .solid-csd .titlebar:backdrop:dir(ltr):not(headerbar), .solid-csd .titlebar:dir(rtl):not(headerbar), .solid-csd .titlebar:dir(ltr):not(headerbar), .solid-csd
+  headerbar:backdrop:dir(rtl), .solid-csd
+  headerbar:backdrop:dir(ltr), .solid-csd
+  headerbar:dir(rtl), .solid-csd
+  headerbar:dir(ltr) {
     margin-left: -1px;
     margin-right: -1px;
     margin-top: -1px;
diff --git a/gtk/theme/Adwaita/gtk-contained.css b/gtk/theme/Adwaita/gtk-contained.css
index c8496e80ec..048cd89188 100644
--- a/gtk/theme/Adwaita/gtk-contained.css
+++ b/gtk/theme/Adwaita/gtk-contained.css
@@ -1936,9 +1936,11 @@ headerbar {
       min-width: 26px;
       margin: 0;
       padding: 0; }
-  .solid-csd .titlebar:backdrop:not(headerbar), .solid-csd .titlebar:not(headerbar), .solid-csd
-  headerbar:backdrop, .solid-csd
-  headerbar {
+  .solid-csd .titlebar:backdrop:dir(rtl):not(headerbar), .solid-csd .titlebar:backdrop:dir(ltr):not(headerbar), .solid-csd .titlebar:dir(rtl):not(headerbar), .solid-csd .titlebar:dir(ltr):not(headerbar), .solid-csd
+  headerbar:backdrop:dir(rtl), .solid-csd
+  headerbar:backdrop:dir(ltr), .solid-csd
+  headerbar:dir(rtl), .solid-csd
+  headerbar:dir(ltr) {
     margin-left: -1px;
     margin-right: -1px;
     margin-top: -1px;