JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <span>I am not vertically centered, but I wishnot vertically centered, but I wishnot vertically centered, but I wish I was :(</span>
</div>

CSS

div
{
    height: 150px;
    border: solid 1px #00f;
    padding: 10px;
    width: 300px;
    position: absolute;
}
span {
    position: absolute;
    display: inline-block;
    top: 50%;
}

JavaScript

$(function() {
    var $span = $('span')
    $span.css('margin-top', -$span.height() / 2);
})