diff --git a/browser/themes/pinstripe/browser.css b/browser/themes/pinstripe/browser.css
index 2560a2205ad..3ac014e9067 100644
--- a/browser/themes/pinstripe/browser.css
+++ b/browser/themes/pinstripe/browser.css
@@ -3459,6 +3459,7 @@ stack[anonid=browserStack][responsivemode] {
   margin: -4px 0 0 0;
   padding: 0;
   border-radius: 0px;
+  background-color: white;
 }
 
 #social-notification-panel .panel-arrow[side="top"] {