JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div id="container">
        <div id="header">
            <ul>
                <li>Item1</li>
                <li>Item2</li>
            </ul>
        </div>
    </div>
</body>

CSS

#container {
    background-color: red;
    width: 400px;
    height: 200px;
    margin: auto;
}

#header ul {
    list-style: none;
    margin-top: 20px; /* I want this to be the margin at the top of the ul, not the container */
}

#header li {
    float: left;
    margin-right: 10px;
}