JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <div class="table">
        <div class="innerLeft">
            <span>Left Column</Span>
        </div>
        
        <div class="innerRight">
            <span>Content with Iframe</span>
        </div>
    </table>
</div>

CSS

html, body {height: 100%}

.table {
    
    display: table;
    height: 100%;
    
}

.innerLeft {

    display: table-cell;
    min-width: 160px;    
    
    background-color: lightblue;
    color: black;
}

.innerRight {
    
    display: table-cell;
    width: 100%;
    vertical-align: top;
    
    background-color: red;
    color: white;
}