JSFiddle - React, Tailwind, and code Playground

HTML

<div class="conteudo">
           <div class="um"></div>
           <div class="mapa"></div>
<div>

CSS

html, body {
        height: 100%;
        margin: 0;
        padding: 0;
      }
	  .conteudo{width: 100%; height:100%;}
	.um{width:100%; height:100px; background: red; float: left;}
	.mapa{width: 100%; height:100%; float:left; background: green;}