cls

cls - Optional CSS class to add to the timeline element.

<div id="timeline" />

<script type="text/javascript">
    $(function () {
        $('#timeline').shieldTimeline({
              cls: "timeline",
              dataSource: {
                    data: [
                        {
                            title: "David F.",
                            text: "Hey! Sure, I will message ...",
                            iconCls: "fa fa-facebook",
                            collapsed: true
                        },
                        {
                            title: "Followed",
                            text: "By J.R. Simpson",
                            iconCls: "fa fa-twitter"
                        }
                    ]
                }
          });
    });
</script>

<style>
      .timeline{
         height: 200px;
      }
</style>