JSFiddle - React, Tailwind, and code Playground

HTML

<div id="navegador">
    <div class="body con_ancho"></div>
    <div class="body"></div>
</div>

CSS

#navegador {
    width: 80%;
    margin: auto;
    border: 1px solid;
}

.body {
    background: #f00;
    margin: 30px;
    height: 100px;
}

.con_ancho {
    width: 100%;
}