JSFiddle - React, Tailwind, and code Playground

HTML

<div id="main_content" >
    <div id="container">
    </div>
</div>

CSS

#main_content {
    width: 300px;
    height: 300px;
    background-color: red;
}

#container {
    width: 100px;
    height: 300px;
    margin: 0 auto;
    background-color:blue;
}