JSFiddle - React, Tailwind, and code Playground

HTML

<div id="header">
    <ul>
        <li>Menu 1</li>
        <li>Menu 2</li>
        <li>Menu 3</li>
        <li>Menu 4</li>
     </ul>
</div>

CSS

body{
    min-height:1000px;
}
#header{
    position: fixed;
    margin:30px;
}
#header ul{
    display:block;
}
#header ul li{
    float:left;
    list-style-type:none;
    width:110px;
    text-align:center;
    line-height:30px;
    padding-bottom:3px;
    background: #ccc;
}