JSFiddle - React, Tailwind, and code Playground

HTML

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

CSS

#main_content {    
    width: 400px; margin: 0 auto;
    min-height: 300px;
    height: auto;
    background-color: #2185C5;
    position: relative;
}

#container {
    width: 50%;
    height: auto;
    margin: 0 auto;background-color: #ccc;
    padding: 10px;
    position: relative;
}