JSFiddle - React, Tailwind, and code Playground

HTML

</head>
<body>

<h1>This is heading 1</h1>
<h2>This is heading 2</h2>
<p>This is a paragraph.</p>
<p>Specifying the font-size in em allows all major browsers to resize the text.
Unfortunately, there is still a problem with older versions of IE. When resizing the text, it becomes larger/smaller than it should.</p>

</body>
</html>
<input type="text" value="adasdadasd">
    <a href="#">Change Font</a>

CSS

html{
    font-size: 12px !important;
}

JavaScript

$('a').on('click',function(){
    $("html")
        .css({
            'cssText':'font-size:1.9rem !important'
        });
});