JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div class="first"></div>
    <div  class="second"></div>
    <div class="third"></div>
    <div class="fourth"></div>
    <br style="clear: both;">
</div>

CSS

#container{
  overflow: hidden;
  background: red;
  width: 500px;
  height: 500px;
}
#container>div{
  border: 1px solid #000;
  width: 30%;
  height: 100px;
  margin: 10px;
  float: left;
}