JSFiddle - React, Tailwind, and code Playground

HTML

<div class='test'>.test</div>
<div class='test2'>.test2<div>

CSS

.test, .test2 {width: 30px; height: 30px; display:block; border: 1px solid #000}
.test2 {color:#FFF; background: #000}

.test:hover+.test2 {
    background: #F00;
}