<div class=“modal is-active”>

<div class="modal-background"></div>
<div class="modal-card">
    <header class="modal-card-head">
        <p class="modal-card-title">Modal title</p>
        <button class="delete" aria-label="close"></button>
    </header>
    <section class="modal-card-body js-video">
        <iframe src="https://www.youtube.com/embed/vsXUIfeX5Oc?rel=0&amp;showinfo=0" frameborder="0" allowfullscreen></iframe>
    </section>
    <footer class="modal-card-foot">
        <button class="button is-success">Save changes</button>
        <button class="button">Cancel</button>
    </footer>
</div>

</div>