body {
   background: url(http://i.imgur.com/VqtFy.jpg);
   background-color:black;
   background-repeat: no-repeat;
   background-position: center;
   display:block;
}

.centered {
  position: fixed;
  top: 50%;
  left: 50%;
  margin-top: 50px;
  margin-left: -20px;
}