JSFiddle - React, Tailwind, and code Playground

HTML

<ul id=menu>
<li>Menu item1
<li>Menu item2
<li>Menu item3
<li>Menu item4
</ul>

CSS

ul {
    position: fixed;
    top: 5%;
    left: 5%;
    width: 50%;
}

ul li {
    width: 100%;
    display: inline-block;
    border: 1px solid;
    margin-bottom: -1px;
}

JavaScript

window.onresize = function(){
    var menu = document.getElementById('menu');
    var width = window.innerWidth;
    menu.style.fontSize = (width / 20)+'px';
};

window.onresize();