pinafore/routes/_components/dialog/ModalDialog.html

<div class="modal-dialog-backdrop" tabindex="-1" data-a11y-dialog-hide></div>
<div class="modal-dialog-contents" role="dialog" aria-label="{{label}}" ref:node>
  <div class="modal-dialog-document" role="document" style="background: {{background || '#000'}};">
    <div class="modal-dialog-header">
      {{#if title}}
        <h1 class="modal-dialog-title">{{title}}</h1>
      {{/if}}
      <div class="close-dialog-button-wrapper">
        <button class="close-dialog-button" data-a11y-dialog-hide aria-label="Close dialog">
          <span aria-hidden="true">&times;</span>
        </button>
      </div>
    </div>
    <slot></slot>
  </div>
</div>
<style>
  :global(#modal-dialog[aria-hidden='true']) {
    display: none;
  }
  .modal-dialog-backdrop {
    position: fixed;
    z-index: 10000;
    left: 0;
    right: 0;
    bottom: 0;
    top: 0;
    background: rgba(51, 51, 51, 0.9);
  }
  .modal-dialog-contents {
    z-index: 10010;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 0;
    border: 1px solid var(--main-border);
    border-radius: 2px;
    display: flex;
    flex-direction: row;
    max-height: calc(100% - 20px);
  }

  .modal-dialog-document {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    max-width: calc(100vw - 20px);
    flex: 1;
  }
  .modal-dialog-header {
    width: 100%;
    background: var(--nav-bg);
    display: flex;
    align-items: center;
  }
  .modal-dialog-title {
    color: var(--nav-text-color);
    padding: 2px 0 2px 10px;
    margin: 0;
    font-size: 1.5em;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  .close-dialog-button-wrapper {
    flex: 1;
    text-align: right;
  }
  .close-dialog-button {
    padding: 0 0 7px;
    background: none;
    border: none;
  }
  .close-dialog-button span {
    padding: 0 10px 7px;
    font-size: 32px;
    color: var(--button-primary-text);
  }
</style>
<script>
  import A11yDialog from 'a11y-dialog'

  export default {
    oncreate() {
      let dialogElement = this.refs.node.parentElement
      let a11yDialog = new A11yDialog(dialogElement)
      a11yDialog.on('hide', () => {
        a11yDialog.destroy()
        this.fire('close')
        this.destroy()
      })
      this.observe('shown', shown => {
        if (shown) {
          a11yDialog.show()
        }
      })
      this.observe('closed', closed => {
        if (closed) {
          setTimeout(() => { // use setTimeout to workaround svelte timing issue
            a11yDialog.hide()
          }, 0)
        }
      })
    }
  }
</script>