JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Header 1</h1>
<p id="para">
    <a href="#" onclick="addElement(); return false;">Add wide element</a>
</p>

CSS

body {margin:0; padding:0}
h1 {background-color:#eee}
.wide {background-color:#00c; color:#fff; width:110%; margin-top:1em; margin-bottom:1em}

JavaScript

function addElement(){
    $("#para").after('<div class="wide">Wide</div>');
    $("a").fadeOut();
    // $("h1").width($(".wide").width()); // <-- trying to avoid needing this
}