<div class="container">
  <button data-my-modal-open="modal-1" class="button">Click Me!</button>
</div>
<div id="debug">
  
</div>

<div class="modal micromodal-slide" id="modal-1" aria-hidden="true">
    <div class="modal__overlay" tabindex="-1" data-my-modal-close>
      <div class="modal__container" role="dialog" aria-modal="true" aria-labelledby="modal-1-title">
        <header class="modal__header">
          <h2 class="modal__title" id="modal-1-title">
            Micromodal
          </h2>
          <button class="modal__close" aria-label="Close modal" data-my-modal-close></button>
        </header>
        <main class="modal__content" id="modal-1-content">
          <p>
            Try hitting the <code>tab</code> key and notice how the focus stays within the modal itself. Also, <code>esc</code> to close modal.
          </p>
        </main>
        <footer class="modal__footer">
          <button class="modal__btn modal__btn-primary">Continue</button>
          <button class="modal__btn" data-my-modal-close aria-label="Close this dialog window">Close</button>
        </footer>
      </div>
    </div>
  </div>
.container {
  margin-top: 1rem;
  margin-left: 1rem;
}

.debug {
  padding: 1rem;
  
  & > p {
    margin-bottom: .5rem;
  }
}

.button {
  border: 1px solid #999;
  background: transparent;
  padding: .5rem 1rem;
  font-weight: bold;
  color: #999;
}

.modal {
  font-family: -apple-system,BlinkMacSystemFont,avenir next,avenir,helvetica neue,helvetica,ubuntu,roboto,noto,segoe ui,arial,sans-serif;
}

.modal__overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0,0,0,0.6);
  display: flex;
  justify-content: center;
  align-items: center;
}

.modal__container {
  background-color: #fff;
  padding: 30px;
  max-width: 500px;
  max-height: 100vh;
  border-radius: 4px;
  overflow-y: auto;
  box-sizing: border-box;
}

.modal__header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal__title {
  margin-top: 0;
  margin-bottom: 0;
  font-weight: 600;
  font-size: 1.25rem;
  line-height: 1.25;
  color: #00449e;
  box-sizing: border-box;
}

.modal__close {
  background: transparent;
  border: 0;
}

.modal__header .modal__close:before { content: "\2715"; }

.modal__content {
  margin-top: 2rem;
  margin-bottom: 2rem;
  line-height: 1.5;
  color: rgba(0,0,0,.8);
}

.modal__btn {
  font-size: .875rem;
  padding-left: 1rem;
  padding-right: 1rem;
  padding-top: .5rem;
  padding-bottom: .5rem;
  background-color: #e6e6e6;
  color: rgba(0,0,0,.8);
  border-radius: .25rem;
  border-style: none;
  border-width: 0;
  cursor: pointer;
  -webkit-appearance: button;
  text-transform: none;
  overflow: visible;
  line-height: 1.15;
  margin: 0;
  will-change: transform;
  -moz-osx-font-smoothing: grayscale;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  -webkit-transform: translateZ(0);
  transform: translateZ(0);
  transition: -webkit-transform .25s ease-out;
  transition: transform .25s ease-out;
  transition: transform .25s ease-out,-webkit-transform .25s ease-out;
}

.modal__btn:focus, .modal__btn:hover {
  -webkit-transform: scale(1.05);
  transform: scale(1.05);
}

.modal__btn-primary {
  background-color: #00449e;
  color: #fff;
}



/**************************\
  Demo Animation Style
\**************************/
@keyframes mmfadeIn {
    from { opacity: 0; }
      to { opacity: 1; }
}

@keyframes mmfadeOut {
    from { opacity: 1; }
      to { opacity: 0; }
}

@keyframes mmslideIn {
  from { transform: translateY(15%); }
    to { transform: translateY(0); }
}

@keyframes mmslideOut {
    from { transform: translateY(0); }
    to { transform: translateY(-10%); }
}

.micromodal-slide {
  display: none;
}

.micromodal-slide.is-open {
  display: block;
}

.micromodal-slide[aria-hidden="false"] .modal__overlay {
  animation: mmfadeIn .3s cubic-bezier(0.0, 0.0, 0.2, 1);
}

.micromodal-slide[aria-hidden="false"] .modal__container {
  animation: mmslideIn .3s cubic-bezier(0, 0, .2, 1);
}

.micromodal-slide[aria-hidden="true"] .modal__overlay {
  animation: mmfadeOut .3s cubic-bezier(0.0, 0.0, 0.2, 1);
}

.micromodal-slide[aria-hidden="true"] .modal__container {
  animation: mmslideOut .3s cubic-bezier(0, 0, .2, 1);
}

.micromodal-slide .modal__container,
.micromodal-slide .modal__overlay {
  will-change: transform;
}
MicroModal.init({
  onShow: modal => {
    const debug = document.getElementById('debug');
    const p = document.createElement('p');
    p.textContent = 'モーダルが開きました。';
    debug.appendChild(p);
  },
  onClose: modal => {
    const debug = document.getElementById('debug');
    const p = document.createElement('p');
    p.textContent = 'モーダルが閉じられました。';
    debug.appendChild(p);
  },
  openTrigger: 'data-my-modal-open',
  closeTrigger: 'data-my-modal-close',
  openClass: 'is-open',
  disableScroll: true,
  disableFocus: true,
  awaitOpenAnimation: false,
  awaitCloseAnimation: true,
  debugMode: true
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/micromodal/0.4.10/micromodal.min.js
  2. https://cdnjs.cloudflare.com/ajax/libs/bootstrap/5.2.3/js/bootstrap.min.js