JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div id="sidebar">
        <p>Sidebar content</p>
    </div>
    <div id="content">
        <iframe id="contentFrame"></iframe>
    </div>
</div>

CSS

html, body {
    height: 100%;
}

#container {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 100%;
    background-color: grey;
}

#sidebar {
    width: 100px;
    float: left;
    background-color: blue;
    height: 100%;
}

#content {
    margin-left: 100px;
    height: 100%;
    background-color: yellow;
}

#contentFrame {        
    border: none;
    padding: 0;
    margin: 0;
    background-color: pink;
    height: 100%;
    display:block;
}