@media (prefers-reduced-motion: no-preference) {
  ::view-transition-old(root) { animation: none; z-index: 0; }
  ::view-transition-new(root) {
    z-index: 1;
    animation: theme-circle-reveal 0.55s cubic-bezier(0.4, 0, 0.2, 1);
  }
  @keyframes theme-circle-reveal {
    from { clip-path: circle(0% at var(--theme-x, 95%) var(--theme-y, 5%)); }
    to   { clip-path: circle(150% at var(--theme-x, 95%) var(--theme-y, 5%)); }
  }
}