Outline

At this point, we have the basics of an application - a user can add new posts which are automatically ordered based on the number of upvotes. Up until now, however, our interface has been lacking in the looks department. We can spruce it up a bit using some basic Bootstrap styling.

Change your index.html file to include Twitter Bootstrap along with a new layout:
<html>
<head>
  <title>Flapper News</title>
  <link href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" rel="stylesheet">

  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.5.7/angular.min.js"></script>
  <script src="app.js"></script>
  <style> .glyphicon-thumbs-up { cursor:pointer } </style>
</head>
<body ng-app="flapperNews" ng-controller="MainCtrl">
  <div class="row">
    <div class="col-md-6 col-md-offset-3">

      <div class="page-header">
        <h1>Flapper News</h1>
      </div>

      <div ng-repeat="post in posts | orderBy:'-upvotes'">
        <span class="glyphicon glyphicon-thumbs-up"
          ng-click="incrementUpvotes(post)"></span>
        {{post.upvotes}}
        <span style="font-size:20px; margin-left:10px;">
          <a ng-show="post.link" href="{{post.link}}">
            {{post.title}}
          </a>
          <span ng-hide="post.link">
            {{post.title}}
          </span>
        </span>
      </div>

      <form ng-submit="addPost()"
        style="margin-top:30px;">
        <h3>Add a new post</h3>

        <div class="form-group">
          <input type="text"
            class="form-control"
            placeholder="Title"
            ng-model="title"></input>
        </div>
        <div class="form-group">
          <input type="text"
          class="form-control"
          placeholder="Link"
          ng-model="link"></input>
        </div>
        <button type="submit" class="btn btn-primary">Post</button>
      </form>

    </div>
  </div>
</body>
</html>

At the top we've included Bootstrap from a CDN. In the body tag, we've made use of Bootstrap's grid system to align our content in the middle of the screen. We've also stylized the posts list and "Add a new post" form to make things a little easier to read. There's a lot more that could be done on this front so feel free to mess around with more styling before (or after) you continue.

(optional) Add your own styles!
 

I finished! On to the next chapter