Absolute Horizontal And Vertical Centering In CSS

index.html

<div>
  I am Horizontal and Vertical centered only by CSS!
</div>

style.css

/* View Full documentation on: http://codepen.io/shshaw/full/gEiDt */

div {
  background: red;
  height: 100px;
  width: 100px;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  margin: auto;
  position: absolute;
}