JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content">
    <div id="div1">This is div1</div>
    <div id="div2">This is div2</div>
</div>

CSS

#div1{
    width:100px;
    height:100px;
    background-color:red;
}

#div2{
    width:100px;
    height:100px;
    background-color:blue;
    display:none;
}

#content > #div1{
    display:block;
}

#content > #div1:hover + #div2 {
    display:block;
}