JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div1">&nbsp;</div>
<div id="div2">&nbsp;</div>

CSS

div {
    position: absolute;
    border: 2px solid black
}
#div1 {
    width: 40%;
    height: calc(40% * 1.2);
}
#div2 {
    width: calc(90% / 4);
    height: 90%;
}