JSFiddle - React, Tailwind, and code Playground

HTML

<aside></aside>
<main></main>

CSS

html,
body {
    margin: 0;
    padding: 0;
    min-height: 100vh;
    min-width: 100vw;
}

body {
    display: flex;
}

aside {
    flex: 1;
    background-color: teal;
}

main {
    flex: 3;
    background-color: maroon;
}