Style AppShell side menu items via "part"

assets/dbp-signature.html.ejs

@@ -51,6 +51,12 @@
             --dbp-override-success-bg-color: #259207;
  /*           --dbp-override-downloaded-bg-color: #9fdf9f; */
         }
+        dbp-signature::part(side-menu-item-selected) {
+            color: black;
+            font-weight: bold;
+            border-left: blue 2px solid;
+            background: none;
+        }
     </style>
 
     <!-- Preloading/Preconnecting -->

toolkit @ 06646f95

-Subproject commit 3587e11ac6ed24aff4e4ed8bea183a22c68ef061
+Subproject commit 06646f957177a30e4047a79f4a32effdaddd92e4