.overlay {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 2;
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  background: var(--color-backdrop);
}
dialog.overlay {
  display: none;
}
dialog.overlay[open] {
  display: grid;
}