Center align div

by nabendu

HTML

<div class="out">
  <div class="in"></div>  
</div>

CSS

.out {
  width: 300px;
  height: 300px;
  background: yellow;
  position: relative
}

.in {
  width: 100px;
  height: 100px;
  background: blue;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}