JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="ta">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi augue mauris, vulputate eu mi scelerisque, faucibus congue lacus. Aenean eros ligula, suscipit tristique dui a, egestas pretium ipsum. Fusce neque justo, fermentum in nunc eget, tempor auctor neque.</textarea>
<div id="slider"></div>

CSS

textarea{
    width:100%;
    height:150px;
    font-size:16px;
}

JavaScript

$("#slider").slider({
    min:10,
    max:40,
    step:2,
    value:16,
    slide:function(e,ui){
        $("#ta").css({'font-size':ui.value+'px','line-height':(ui.value+4)+'px'});
    }
});