Disable single toolbar mode and adjust UI margins for improved layout consistency

src/browser/base/content/zen-styles/zen-browser-ui.css

@@ -78,13 +78,13 @@
 }
 
 :root:not([inDOMFullscreen='true']):not([chromehidden~='location']):not([chromehidden~='toolbar']) {
-  & #zen-appcontent-wrapper {
+  & #zen-tabbox-wrapper {
     margin: var(--zen-element-separation);
     margin-left: 0;
     margin-top: 0;
   }
 
-  &[zen-right-side='true'] #zen-appcontent-wrapper {
+  &[zen-right-side='true'] #zen-tabbox-wrapper {
     margin-right: 0;
   }
 }

src/browser/base/content/zen-styles/zen-glance.css

@@ -31,8 +31,7 @@
       animation: zen-glance-content-animation-out .5s ease-in-out forwards !important;
 
       & browser {
-        opacity: 0;
-        transition: opacity .3s ease-in-out;
+        opacity: 1 !important;
       }
 
       & #zen-glance-sidebar-container {

src/browser/base/content/zen-styles/zen-tabs/vertical-tabs.css

@@ -28,7 +28,6 @@
   :root:not([zen-window-buttons-reversed='true']) .titlebar-buttonbox-container {
     margin-left: auto;
     width: fit-content;
-    margin-right: var(--zen-element-separation);
   }
 
   #TabsToolbar > * {