JSFiddle - React, Tailwind, and code Playground

HTML

<head>
    <title></title>
    <style>
        .u .test1
        {
            background-color: gray;
        }
        .u > .test1
        {
            background-color: yellow;
        }
        
        .u .test1
        {
            background-color: red
        }
    </style>
</head>
<body>
<div class="u">
    <div class='test1'>?</div>
</div>
</body>