JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <span>Boooooooooooooooooooooooooooooooooooooo boo</span>
    <span>Shrink me, please</span>
</div>

CSS

div { display: flex; }
span { flex: 1 1 auto; }
span:first-child { background: #ccc }