JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box">
        <div class="box-in"></div>
    </div>
    <div class="box">
        <div class="box-in"></div>
    </div>

CSS

body {
    position: fixed;
    width: 100%;
    border: none;
    display: table;
    table-layout: fixed;
 	  padding: 0;
    margin: 0;
    top: 0;
    left: 0;
}

.box {
    border: none;
    display: table-cell;
    height: 100vh;
    background-color: yellow;
    box-sizing:border-box;
    padding:10px;
}

.box-in {
	  border: solid 1px;
    height: 100%;
}