JSFiddle - React, Tailwind, and code Playground

HTML

<div class="div1">This div is centered with a max-width, and will stretch with the page</div>
<br>
<div class="div2">This div has a margin of 20px on the left and right side</div>

CSS

.div1 {
    background-color: #eee;
    max-width: 600px;
    margin: auto;
}

.div2 {
    background-color: #eee;
    margin-left: 20px;
    margin-right: 20px;
}