diff --git a/browser/themes/shared/browser-shared.css b/browser/themes/shared/browser-shared.css
index 61119b7564d37e55f49dab7e6e14faafb4baa298..bcaad1a231cc839579ed209307c8e95cfb4c37de 100644
--- a/browser/themes/shared/browser-shared.css
+++ b/browser/themes/shared/browser-shared.css
@@ -27,6 +27,8 @@
 @import url("chrome://browser/skin/UITour.css");
 @import url("chrome://browser/skin/formautofill-notification.css");
 
+@import url("chrome://browser/skin/zen-browser-shared.css");
+
 @namespace html url("http://www.w3.org/1999/xhtml");
 
 :root,
@@ -75,7 +77,7 @@ body {
   --short-notification-gradient: #9059FF;
 
   --button-bgcolor: color-mix(in srgb, currentColor 13%, transparent);
-  --button-hover-bgcolor: color-mix(in srgb, currentColor 17%, transparent);
+  --button-hover-bgcolor: color-mix(in srgb, currentColor 15%, transparent);
   --button-active-bgcolor: color-mix(in srgb, currentColor 30%, transparent);
   --button-color: currentColor;
   --button-primary-bgcolor: AccentColor;
@@ -181,7 +183,6 @@ body {
   appearance: none;
 
   /* Toolbar / content area border */
-  border-bottom: 0.01px solid var(--chrome-content-separator-color);
 
   background-color: var(--toolbox-non-lwt-bgcolor);
   color: var(--toolbox-non-lwt-textcolor);
@@ -190,37 +191,13 @@ body {
   transition: background-color var(--inactive-window-transition);
 
   &:-moz-window-inactive {
-    background-color: var(--toolbox-non-lwt-bgcolor-inactive);
     color: var(--toolbox-non-lwt-textcolor-inactive);
   }
 
   &[fullscreenShouldAnimate] {
     transition: 0.8s margin-top ease-out;
   }
-
-  :root[customizing] & {
-    border-bottom-style: none;
-  }
-
-  :root[lwtheme] & {
-    background-image: var(--lwt-additional-images);
-    background-repeat: var(--lwt-background-tiling);
-    background-position: var(--lwt-background-alignment);
-    background-color: var(--lwt-accent-color);
-    color: inherit;
-
-    &:-moz-window-inactive {
-      background-color: var(--lwt-accent-color-inactive, var(--lwt-accent-color));
-    }
-  }
-
-  /* When a theme defines both theme_frame and additional_backgrounds, show
-     the latter atop the former. */
-  :root[lwtheme-image] & {
-    background-image: var(--lwt-header-image), var(--lwt-additional-images);
-    background-repeat: no-repeat, var(--lwt-background-tiling);
-    background-position: right top, var(--lwt-background-alignment);
-  }
+  
 }
 
 .browser-toolbar {