JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://raw.githack.com/Nycto/PicoModal/master/src/picoModal.js"></script>

CSS

.footer {
    position: absolute;
    bottom: 0;
    background: #efefef;
    width: 100%;
    left: 0;
    padding: 10px;
    box-sizing: border-box;
    margin: 0;
    text-align: right;
}
.pico-content > :first-child {
    margin-bottom: 50px;
}

JavaScript

picoModal({
    content: "<p>Ah, the pitter patter of tiny feet in huge combat boots.</p>" +
        "<p class='footer'>" +
        "<button class='cancel'>Cancel</button> " +
        "<button class='ok'>Ok</button>" +
        "</p>"
}).afterCreate(modal => {
    modal.modalElem().addEventListener("click", evt => {
        if (evt.target && evt.target.matches(".ok")) {
            modal.close(true);
        } else if (evt.target && evt.target.matches(".cancel")) {
            modal.close();
        }
    });
}).afterClose((modal, evt) => {
    alert(evt.detail ? "Ok" : "Cancelled");
}).show();