JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div1">
    <div id="div11" />
	<div id="div12" />
	<div id="div13"/>
</div>

CSS

#div1 {
    width: 100%;
	height: 100%;
	background-color: red;
  }
   #div11 {
    width: 30px;
	height: 30px;
	 background-color: orange;
  }
  #div12 {
    width: 30px;
	height: 30px;
	background-color: blue;
  }
  #div13 {
    width: 30px;
	height: 30px;
	background-color: yellow;
  }