* {
  font-family:Tahoma;
}
body {
  background:url(mocmoc.png) repeat center center fixed;
  margin:0
}
.box {
  width:400px;
  
  background-color:white;
  border:solid 3px #333;
  box-shadow:4px 3px 5px #333;
  text-align:center;
  padding:30px 10px;
}
.centered {
  position:fixed;
  top:50%;
  left:50%;
  /* bring your own prefixes */
  transform:translate(-50%,-50%);
}