JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div id="up">Text<br />Text<br />Text<br /></div>
    <div id="down">Text<br />Text<br />Text<br /></div>
</div>

CSS

#container { width: 300px; height: 300px; border:1px solid red;}
#up { background: green; height: 63px; float:left; width: 100% }
#down { background:pink; padding-top: 63px; height: 100%; box-sizing: border-box; }