diff --git a/gtk/resources/theme/Adwaita/_common.scss b/gtk/resources/theme/Adwaita/_common.scss
index 44df0679a3..7b95e99ca3 100644
--- a/gtk/resources/theme/Adwaita/_common.scss
+++ b/gtk/resources/theme/Adwaita/_common.scss
@@ -423,6 +423,10 @@ GtkLinkButton.button {
           @extend %top_button;
           @include button(insensitive, $noedge: true);
         }
+        &:backdrop {
+          @extend %top_button;
+          @include button(backdrop);
+        }
       }
       &:last-child {
         @extend %bottom_button;
@@ -439,9 +443,10 @@ GtkLinkButton.button {
           @extend %bottom_button;
           @include button(insensitive);
         }
-      }
-      &:backdrop {
-        @include button(backdrop);
+        &:backdrop {
+          @extend %bottom_button;
+          @include button(backdrop);
+        }
       }
       &:backdrop:insensitive {
         @include button(backdrop-insensitive);
diff --git a/gtk/resources/theme/Adwaita/gtk-contained-dark.css b/gtk/resources/theme/Adwaita/gtk-contained-dark.css
index cef7567d21..35a8949b57 100644
--- a/gtk/resources/theme/Adwaita/gtk-contained-dark.css
+++ b/gtk/resources/theme/Adwaita/gtk-contained-dark.css
@@ -545,6 +545,15 @@ GtkLinkButton.button {
     text-shadow: none;
     icon-shadow: none;
     box-shadow: inset 0 1px rgba(255, 255, 255, 0); }
+  .spinbutton.vertical .button:first-child:backdrop {
+    border-width: 1px;
+    border-style: solid;
+    color: #c9cbc9;
+    border-color: #1e2222;
+    background-image: linear-gradient(to bottom, #393f3f);
+    text-shadow: none;
+    icon-shadow: none;
+    box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px rgba(255, 255, 255, 0); }
 .spinbutton.vertical .button:last-child {
   border-width: 1px;
   border-style: solid;
@@ -581,15 +590,15 @@ GtkLinkButton.button {
     text-shadow: none;
     icon-shadow: none;
     box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px rgba(238, 238, 236, 0.1); }
-.spinbutton.vertical .button:backdrop {
-  border-width: 1px;
-  border-style: solid;
-  color: #c9cbc9;
-  border-color: #1e2222;
-  background-image: linear-gradient(to bottom, #393f3f);
-  text-shadow: none;
-  icon-shadow: none;
-  box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px rgba(255, 255, 255, 0); }
+  .spinbutton.vertical .button:last-child:backdrop {
+    border-width: 1px;
+    border-style: solid;
+    color: #c9cbc9;
+    border-color: #1e2222;
+    background-image: linear-gradient(to bottom, #393f3f);
+    text-shadow: none;
+    icon-shadow: none;
+    box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px rgba(255, 255, 255, 0); }
 .spinbutton.vertical .button:backdrop:insensitive {
   border-width: 1px;
   border-style: solid;
@@ -599,10 +608,10 @@ GtkLinkButton.button {
   box-shadow: inset 0 1px rgba(255, 255, 255, 0); }
 .spinbutton.vertical.entry {
   border-radius: 0; }
-.spinbutton.vertical .button:first-child, .spinbutton.vertical .button:first-child:active, .spinbutton.vertical .button:first-child:hover, .spinbutton.vertical .button:first-child:insensitive {
+.spinbutton.vertical .button:first-child, .spinbutton.vertical .button:first-child:active, .spinbutton.vertical .button:first-child:hover, .spinbutton.vertical .button:first-child:insensitive, .spinbutton.vertical .button:first-child:backdrop {
   border-radius: 3px 3px 0 0;
   border-bottom-width: 0; }
-.spinbutton.vertical .button:last-child, .spinbutton.vertical .button:last-child:active, .spinbutton.vertical .button:last-child:hover, .spinbutton.vertical .button:last-child:insensitive {
+.spinbutton.vertical .button:last-child, .spinbutton.vertical .button:last-child:active, .spinbutton.vertical .button:last-child:hover, .spinbutton.vertical .button:last-child:insensitive, .spinbutton.vertical .button:last-child:backdrop {
   border-radius: 0 0 3px 3px;
   border-top-width: 0; }
 
diff --git a/gtk/resources/theme/Adwaita/gtk-contained.css b/gtk/resources/theme/Adwaita/gtk-contained.css
index bd7821f5ab..9bc7dca458 100644
--- a/gtk/resources/theme/Adwaita/gtk-contained.css
+++ b/gtk/resources/theme/Adwaita/gtk-contained.css
@@ -545,6 +545,15 @@ GtkLinkButton.button {
     text-shadow: none;
     icon-shadow: none;
     box-shadow: inset 0 1px rgba(255, 255, 255, 0); }
+  .spinbutton.vertical .button:first-child:backdrop {
+    border-width: 1px;
+    border-style: solid;
+    color: #54595a;
+    border-color: #a8a8a8;
+    background-image: linear-gradient(to bottom, #ededed);
+    text-shadow: none;
+    icon-shadow: none;
+    box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px rgba(255, 255, 255, 0); }
 .spinbutton.vertical .button:last-child {
   border-width: 1px;
   border-style: solid;
@@ -581,15 +590,15 @@ GtkLinkButton.button {
     text-shadow: none;
     icon-shadow: none;
     box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px white; }
-.spinbutton.vertical .button:backdrop {
-  border-width: 1px;
-  border-style: solid;
-  color: #54595a;
-  border-color: #a8a8a8;
-  background-image: linear-gradient(to bottom, #ededed);
-  text-shadow: none;
-  icon-shadow: none;
-  box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px rgba(255, 255, 255, 0); }
+  .spinbutton.vertical .button:last-child:backdrop {
+    border-width: 1px;
+    border-style: solid;
+    color: #54595a;
+    border-color: #a8a8a8;
+    background-image: linear-gradient(to bottom, #ededed);
+    text-shadow: none;
+    icon-shadow: none;
+    box-shadow: inset 0 1px rgba(255, 255, 255, 0), 0 1px rgba(255, 255, 255, 0); }
 .spinbutton.vertical .button:backdrop:insensitive {
   border-width: 1px;
   border-style: solid;
@@ -599,10 +608,10 @@ GtkLinkButton.button {
   box-shadow: inset 0 1px rgba(255, 255, 255, 0); }
 .spinbutton.vertical.entry {
   border-radius: 0; }
-.spinbutton.vertical .button:first-child, .spinbutton.vertical .button:first-child:active, .spinbutton.vertical .button:first-child:hover, .spinbutton.vertical .button:first-child:insensitive {
+.spinbutton.vertical .button:first-child, .spinbutton.vertical .button:first-child:active, .spinbutton.vertical .button:first-child:hover, .spinbutton.vertical .button:first-child:insensitive, .spinbutton.vertical .button:first-child:backdrop {
   border-radius: 3px 3px 0 0;
   border-bottom-width: 0; }
-.spinbutton.vertical .button:last-child, .spinbutton.vertical .button:last-child:active, .spinbutton.vertical .button:last-child:hover, .spinbutton.vertical .button:last-child:insensitive {
+.spinbutton.vertical .button:last-child, .spinbutton.vertical .button:last-child:active, .spinbutton.vertical .button:last-child:hover, .spinbutton.vertical .button:last-child:insensitive, .spinbutton.vertical .button:last-child:backdrop {
   border-radius: 0 0 3px 3px;
   border-top-width: 0; }