fix issue #19: add a hack to show external sites in the top menu with navigation

templates/css/stylesheet.php

@@ -12,11 +12,16 @@
     #appmenu {
         display: none;
     }
+
+    #appmenu + nav {
+        display: none;
+    }
+<?php else: ?>
+    .app-hidden {
+        opacity: 0;
+    }
 <?php endif; ?>
 
-#appmenu + nav {
-    display: none;
-}
 
 <?php if ($_['opener-only'] === true): ?>
     #nextcloud {
@@ -42,11 +47,6 @@
         visibility: hidden;
     }
 
-    #side-menu.hide-opener .side-menu-apps-list {
-        /* height: calc(100vh);
-        top: 0; */
-    }
-
     <?php if ($_['size-text'] === 'hidden'): ?>
         #side-menu, .side-menu-apps-list {
             <?php if ($_['size-icon'] === 'big'): ?>