JSFiddle - React, Tailwind, and code Playground

HTML

<div id="box">
    <div id="innerBox" onclick="blabla()"></div>
</div>

CSS

#box {
    position:relative;
    display:block;
    height:100px;
    width:100px;
    background-color:red;
}
#innerBox {
    display:block;
    height:25px;
    width:25px;
    background-color:black;
    z-index:1;
}
#innerBox:hover #box{
   width:1px;
}

JavaScript

function blabla()
{
    document.getElementById("box").style.color = "blue";
}