Bootstrap CSS class .fade

    <div class="m-4" data-class="btn-close">
        <div class="alert alert-warning alert-dismissible fade show" role="alert">
            <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Quasi quae voluptatibus excepturi, pariatur dolor perferendis deleniti quas.</p>
            <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
        </div>
    </div>