JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div id="container">
        <div id="center">
             <h1>center</h1> 
            <div id="right">
                 <h1>right</h1> 
            </div>
        </div>
    </div>
</body>

</html>

CSS

h1 {

    display: inline-block;

}

#center {

    background-color: green;

    float: left;

    width: 100%;

}

#right {

    background-color: red;

    float: right;

    width: 200px;

}