diff --git a/src/browser/base/content/zen-styles/zen-urlbar.css b/src/browser/base/content/zen-styles/zen-urlbar.css
index 71f589b7c..eb146580e 100644
--- a/src/browser/base/content/zen-styles/zen-urlbar.css
+++ b/src/browser/base/content/zen-styles/zen-urlbar.css
@@ -251,6 +251,7 @@ button.popup-notification-dropmarker {
 /* Notification Stack */
 
 .notificationbox-stack {
+  background: transparent;
 
   &[notificationside="top"] {
     position: absolute;