JSFiddle - React, Tailwind, and code Playground

HTML

<div id="a">Div A</div>
<div id="b">Div B</div>

CSS

body {
    display:block;
}
div {
    display:block;
    margin:10px;
    background:red;
}
@media all and (min-width:480px) {
    body {
        display:table;
        table-layout:fixed;
        border-spacing:10px;
        width:100%;
    }
    div {
        display:table-cell;
        margin:10px;
        background:blue;
    }
}