JSFiddle - React, Tailwind, and code Playground

HTML

<div class="conteudo-modelo-3-0 clearfix">
  <div class="conteudo-modelo-3-1"></div>
</div>

CSS

.clearfix:after{
  content: "";
  display: table;
  clear: both;
}


.conteudo-modelo-3-0 {
  width: 500px;
  height: auto;
  margin: 0 auto;
  background-color: red;
  clear: both;
}

.conteudo-modelo-3-1{    
  position: relative;
  width: 500px;
  height: 120px;
  float: right;
}