JSFiddle - React, Tailwind, and code Playground

HTML

<div class="roundbox">
    <h3>Dashboard</h3>
    <ul>
        <li><a href="http://google.com">Voertuigen</a></li>
        <li>Klanten</li>
        <li>Factures</li>
        <li>Boetes</li>
        <li>Onderhoud</li>
    </ul>
</div>

CSS

div.roundbox {
    border-radius: 15px;
    width: 120px;
    padding: 10px;
    background: #BEBEBE;
}

div.roundbox ul {
    list-style: none;
}

div.roundbox ul li {
    height: 40px;
    background: #E5E5E5;
}

div.roundbox ul li:last-child
{
    border-bottom-left-radius: 5px;
    border-bottom-right-radius: 5px;
}

div.roundbox h3
{
    border-top-left-radius: 5px;
    border-top-right-radius: 5px;

    height: 40px;
    background-color: #00BEE5;
}