JSFiddle - React, Tailwind, and code Playground

HTML

<div id="header">

    <ul>
        <li>Button1</li>
        <li>Button2</li>
        <li>Button3</li>
    </ul>
        
</div>

CSS

#header { position:relative; width:600px; height:150px; border:1px solid #000; }
#header ul { position:absolute; bottom:1px; display:block; width:580px; padding:0 0 0 20px; }
#header li { display:inline; margin:0px 20px; border:1px solid #000; font-size:22px; padding:2px 7px; background:#c1c1c1; }