closed shadowRoot and changed pages, components, layout to extend base class

src/pages/not-found/NotFoundElement.ts

@@ -2,10 +2,10 @@ import { controller } from "@github/catalyst";
 import { closest, update } from "core/utils";
 import { html, render } from "@github/jtml";
 import { AppMainElement } from "components/";
+import { BasePageElement } from "common/";
 
 @controller
-class NotFoundElement extends HTMLElement {
-    @closest appMain: AppMainElement;
+class NotFoundElement extends BasePageElement {
     constructor() {
         super();
     }
@@ -19,8 +19,4 @@ class NotFoundElement extends HTMLElement {
             <div><app-link data-to="/" data-title="Homepage"></app-link></div>
         `;
     };
-
-    update = () => {
-        render(this.render(), this);
-    };
 }