JSFiddle - React, Tailwind, and code Playground

HTML

<div class="centered">center
    <div class="widest">widest</div>
</div>

CSS

.centered{
    margin: 0 auto;
    width: 960px;
    height: 300px;
    background-color: yellow;
}

.widest {
    height: 200px;
    margin: 0 calc( 1px - ((100vw - 960px) / 2) - 1px);
    background-color: red;
}