::view-transition-new(root) {
  mask: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 40 40"><circle cx="20" cy="20" r="20" fill="white"/></svg>')
    center / 0 no-repeat;

  animation: scale 1s;
  animation-fill-mode: both;
}

::view-transition-old(root),
.dark::view-transition-old(root) {
  animation: none;
  animation-fill-mode: both;
  z-index: -1;
}

.dark::view-transition-new(root) {
  animation: scale 1s;
  animation-fill-mode: both;
}

@keyframes scale {
  to {
    mask-size: 200vmax;
  }
}