<div class="parent">
  <div class="child" />
</div>
.parent {
  width: 300px;
  height: 300px;
  background: black;
  margin-top: 20px;
}

.child {
  width: 100px;
  height: 100px;
  background: blue;
  margin-top: 100px;
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.