JSFiddle - React, Tailwind, and code Playground

by Aaron Bird

HTML

<div class="el-3 container">
	<div class="child" style="position:absolute;">
	</div>
</div>
<br>
<div class="el-4 container"  style="box-sizing: border-box">
	<div class="child" style="position:absolute;box-sizing: border-box"></div>
</div>

CSS

.container {
      width: 150px;
      height: 150px;
      background: yellow;
      border: 10px dashed black;
      position:relative;
      padding:10px;
  }
  .child {
      width: 100%;
      height: 100%;
      background:  blue;
  }