Customize how it enters the stage

@media (prefers-reduced-motion: no-preference) {
  .sidenav {
    view-transition-name: sidenav;
  }
  
  ::view-transition-old(sidenav) {
    animation: 
      var(--animation-fade-out) forwards,
      var(--animation-scale-down) forwards;
  }
  ::view-transition-new(sidenav) {
    animation: 
      var(--animation-fade-in) forwards,
      var(--animation-slide-in-right) forwards;
  }
}