add navbar design

src/app/app.component.css

@@ -0,0 +1,3 @@
+.list-group{
+    padding-top: 30px;
+}

src/app/app.component.html

@@ -1,9 +1,12 @@
-<div>
-  <h2>wikipedia search</h2>
-  <input (input)="term$.next($event.target.value)">
-  <ul>
-    <li *ngFor="let item of items; index as i">
+  <nav class="navbar sticky-top navbar-dark bg-primary">
+    <a class="navbar-brand" href="#!">Wikipedia Search Api</a>
+    <input class="center-block" (input)="term$.next($event.target.value)" placeholder="Type Here...">
+  </nav>
+
+<div class="container">
+  <ul class="list-group">
+    <li class="list-group-item" *ngFor="let item of items; index as i">
         <a href="{{links[i]}}">{{item}}</a>
     </li>
   </ul>
-</div>
+</div>

src/styles.css

@@ -1 +1 @@
-/* You can add global styles to this file, and also import other style files */
+/* You can add global styles to this file, and also import other style files */