JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
        <div class="right">Right</div>
        <div class="left">
            Left fluid
            <br/>multiple rows
        </div>
    </div>

CSS

.container {
        display: flex;
        width: 100%;
        outline: 1px dotted gray;
    }
    .right {
        order: 2;
        flex: 0 0 auto;
        border: 1px solid green;
    }
    .left {
        flex: 1 0 auto;
        border: 1px solid red;
    }