<div class="vertical"> <div class="content"></div> </div>
.vertical {
position: relative;
width: 200px;
height: 200px;
margin: 0 auto;
margin-top: 10px;
border: 1px solid blue;
}
.content {
position: absolute;
width: 50px;
height: 50px;
background-color: red;
margin: auto;
left: 0;
right: 0;
top: 0;
bottom: 0;
}