diff --git a/browser/themes/windows/browser.css b/browser/themes/windows/browser.css
index 007aec91e089a1d2df20235890b268b820b0a529..a03a0d7b7837f6315f47f76a4491bf08d96e00e0 100644
--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -31,7 +31,6 @@
     /* 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));
     }
   }
 
@@ -56,7 +55,7 @@
 
 /* This is needed for Windows 10, see bug 1961257 */
 @media (-moz-windows-accent-color-in-titlebar) {
-  :root[customtitlebar][sizemode="normal"] #navigator-toolbox {
+  :root[customtitlebar][sizemode="normal"] #browser {
     border-top: .5px solid ActiveBorder;
     &:-moz-window-inactive {
       border-top-color: InactiveBorder;