JSFiddle - React, Tailwind, and code Playground

HTML

<p id="default">1em abgp</p>
<p id="point8">0.8em abgp</p>
<p id="half">0.5em abgp</p>
<p id="zero">0.0em abgp</p>

CSS

p {
    font-size: 36px;
    font-family: Arial, sans-serif;
    margin: 40px 20px;
    border-bottom: 1px solid #ccc;
}

#default {
    line-height: 2em;
}

#point8 {
    line-height: 0.8em;
}

#half {
    line-height: 0.5em;
}

#zero {
    line-height: 0;
}