Remove gap between 2 divs

I am using material css for a small project, specifically the cards. I have 2 cards in my page and want to remove the space between them. I thought I would be fairly trivial but cant seem to apply any css to my content. Heres my code: <div class="container"> <div class="row"> <div class="col-md-6 col-md-offset-3"> <div class="card-panel blue accent-3"> <div class="card-content"> <span class="card-title white-text"><i class="fa fa-bars" aria-hidden="true"> </i> title</span> </div> </div> </div> </div> <div class="row" id="second"> <div class="col-md-6 col-md-offset-3"> <div class="card-panel white blue-text"> <div class="card-content"> <ul> <li><a href="#">report 1</a></li> <li><a href="#">report 2</a></li> <li><a href="#">report 3</a></li> <li><a href="#">report 4</a></li> <li><a href="#">report 5</a></li> </ul> </div> </div> </div> </div> </div> CSS: <style type="text/css"> body { background-color: #e7e6ef; } .row { width: 500px; margin-left: 50%; } #second { margin-top: 0; !important; } </style> How it looks: However I cant seem to remove the gap between the 2 cards nor center them. Any help is greatly appreciated