<div id="container">

<div class="box">
<span>.box</span>
<div class="elm">.elm</div>
</div>

</div>

body{margin: 0;padding: 0;}
#container {
  width: 90%;
	margin: 0 auto;
  padding-top: 20px;
}
.elm {
  width: 20%;
  height: 100px;
  line-height: 100px;
  background: #ccc;
  text-align: center;
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%,-50%);
  transform: translate(-50%,-50%);
}
.box {
	background: #eee;
	border: 1px solid #ddd;
  text-align: center;
  position: relative;
  height: 200px;
}
.box span {
  width: 65%;
  display: inline-block;
  position: absolute;
  top: 2%;
  left: 16%;
}