JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
    <li>4</li>
    <li>5</li>
    <li>6</li>
</ul>

CSS

ul {
        display: flex;
        display: -webkit-flex;

        flex-direction: row;
        -webkit-flex-direction: row;

        flex-wrap: wrap;
        -webkit-flex-wrap: wrap;

        justify-content: center;
        -webkit-justify-content: center;
    margin: 0;
    padding: 0;
}

li {
    list-style-type: none;
    border: 1px solid gray;
    margin: 15px;
    padding: 5px;
    width: 200px;
}