Implement 404 page

app/router.js

@@ -89,6 +89,7 @@ AppRouter.map(function () {
   this.route('module', { path: '/modules/:module' });
   this.route('data-class', { path: '/data/classes/:class' });
   this.route('data-module', { path: '/data/modules/:module' });
+  this.route('not-found', { path: '/*' });
 });
 
 /*

app/routes/not-found.js

@@ -0,0 +1,14 @@
+import Route from '@ember/routing/route';
+import { inject as service } from '@ember/service';
+
+export default class NotFoundRoute extends Route {
+  @service fastboot;
+
+  beforeModel() {
+    if (!this.fastboot.isFastBoot) {
+      return;
+    }
+
+    this.fastboot.response.statusCode = 404;
+  }
+}

app/styles/app.css

@@ -109,6 +109,18 @@ a.class-field-description--link:hover svg {
   fill: var(--color-brand);
 }
 
+.whoops {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  padding: var(--spacing-6)
+}
+
+.whoops img {
+    width: 240px;
+    margin: var(--spacing-2);
+}
+
 @media (min-width: 845px) {
   .es-header {
     padding: 0 var(--spacing-4);
@@ -124,3 +136,20 @@ a.class-field-description--link:hover svg {
     margin-top: var(--spacing-4);
   }
 }
+
+@media (max-width: 450px) {
+  .whoops {
+    flex-direction: column;
+    padding: var(--spacing-3);
+  }
+
+  .whoops img {
+    width: 80%;
+    margin: var(--spacing-4);
+  }
+
+  .whoops__message {
+    margin: var(--spacing-2);
+    text-align: center;
+  }
+}

app/templates/not-found.hbs

@@ -0,0 +1,7 @@
+<article class="whoops">
+  <img src="/assets/images/stinky-fish.png" alt="tomster stinky fish"/>
+  <div class="whoops__message">
+    <h2>Ack! 404 friend, you're in the wrong place</h2>
+    <LinkTo @route='index'>Click here to go home</LinkTo>
+  </div>
+</article>

tests/unit/routes/not-found-test.js

@@ -0,0 +1,11 @@
+import { module, test } from 'qunit';
+import { setupTest } from 'ember-qunit';
+
+module('Unit | Route | not-found', function (hooks) {
+  setupTest(hooks);
+
+  test('it exists', function (assert) {
+    let route = this.owner.lookup('route:not-found');
+    assert.ok(route);
+  });
+});