<div>
   <span></span>
</div>

div {
  background: rgba( 0, 153, 255, 0.8 );
  font-size: 0;
  line-height: 3.5rem;
  height: 4rem;
}
span {
  background: rgba( 255, 255, 0, 0.8 );
  font-size: 0;
  line-height: 1rem;
  padding: 1rem;
  vertical-align: bottom;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.