diff --git a/lib/app-layout/style.scss b/lib/app-layout/style.scss
index e8484a9c2..f681efe19 100644
--- a/lib/app-layout/style.scss
+++ b/lib/app-layout/style.scss
@@ -10,6 +10,10 @@
       width: 0;
       transition: width .2s ease-in-out, opacity .2s ease-in-out;
     }
+    .theme-color-border {
+      border-left-width: 0px;
+      transition: border-left-width .2s;
+    }
   }
 
   &.is-navigation-open {