JSFiddle - React, Tailwind, and code Playground

HTML

<button type="button" id="mostrar-msg">Assistir</button>

<div id="modal-assistir" class="modal-back">
    <div class="modal">
        <a class="close" href="#" data-toggle="modal-assistir">Fechar</a>
        <form>
            <label for="email">Insira seu email para assistir</label>
            <br>
            <input type="email" name="email">
            <br><br>
            <button type="button">Enviar</button>
        </form>
    </div>
</div>

CSS

.modal-back {
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    position: fixed;
    z-index: 10;
    display: none;
    top: 0; left: 0; right: 0; bottom: 0;
}
.modal-back.toggled {
    display: block;
}

.modal {
    width: 500px;
    background-color: #fff;
    padding: 20px;
    z-index: 20;
    border-radius: 5px;
    border: 1px solid #424242;
    position: fixed;
    top: 50%;
    margin-left: auto;
}
.modal label {
    font-size: 20px;
    font-weight: bold;
}
.modal a.close {
    float: right;
    text-transform: uppercase;
    text-decoration: none;
    font-size: 10px;
}

JavaScript

$('#mostrar-msg').click(function() {
    $('#modal-assistir').addClass('toggled');
});

$('a.close').click(function(e) {
    e.preventDefault();
    
    var target = '#' + $(this).data('toggle');
    $(target).removeClass('toggled');
});