<div class="row">
    <div class="col-md-12">
        <div id="followingBalls">
            <div id="ball-1" class="ball"></div>
            <div id="ball-2" class="ball"></div>
            <div id="ball-3" class="ball"></div>
            <div id="ball-4" class="ball"></div>
        </div>
    </div>
</div>
