JSFiddle - React, Tailwind, and code Playground

HTML

<p>1 em body text</p>
<i>2em = twice as big as body text</i>
<p>Resize the window to see the font-size change because I changed the body font-size with media queries</p>

CSS

body{font-size:100%;}
i{font-size: 2em;}


@media screen and (min-width: 500px) {
    body{font-size: 150%;}
}

@media screen and (min-width: 700px) {
    body{font-size: 200%;}
}