JSFiddle - React, Tailwind, and code Playground

HTML

<div class="rojo">Soy rojo</div>
<div class="azul">Soy azul</div>

CSS

div {
    width: 50%;
    height: 100px;
}

div.rojo {
    float: right;
    background: red;
}

div.azul {
    float: left;
    background: deepskyblue;
}

div.rojo:hover + div.azul {
    background: grey;
}