diff --git a/browser/themes/windows/browser.css b/browser/themes/windows/browser.css
index 3e75a5f366e76acf4b9457a510b58b0cb8af580f..99b5712d533e99f3bb3f13c1485e771ab66731cd 100644
--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -34,7 +34,6 @@
         /* stylelint-disable-next-line media-query-no-invalid */
         @media -moz-pref("widget.windows.mica.toplevel-backdrop", 2) {
           /* For acrylic, do the same we do for popups to guarantee some contrast */
-          background-color: light-dark(rgba(255, 255, 255, .6), rgba(0, 0, 0, .6));
         }
       }
     }
@@ -57,7 +56,7 @@
       }
     }
 
-    &[sizemode="normal"] #navigator-toolbox {
+    &[sizemode="normal"] #browser {
       border-top: .5px solid ActiveBorder;
       &:-moz-window-inactive {
         border-top-color: InactiveBorder;
