Refactor zen-compact-mode.css for improved UI layout

Author: mr-cheffy

src/browser/base/content/zen-styles/zen-compact-mode.css

@@ -150,6 +150,10 @@
     padding-left: var(--zen-element-separation) !important;
   }
 
+  #zen-appcontent-navbar-container { 
+    z-index: 2;
+  }
+
   @media (-moz-bool-pref: 'zen.view.compact.hide-toolbar') {
     #zen-appcontent-navbar-container {
       --urlbar-height: unset;
@@ -160,10 +164,11 @@
       width: 100%;
       border-bottom-left-radius: 8px;
       border-bottom-right-radius: 8px;
+      border-top-left-radius: env(-moz-gtk-csd-titlebar-radius);
+      border-top-right-radius: env(-moz-gtk-csd-titlebar-radius);
       border-bottom: 1px solid var(--zen-colors-border);
       top: 0;
       background: var(--zen-colors-tertiary);
-      z-index: 2;
       transition: 0.2s ease-in-out;
     }