text: const ANIMATION_TIME = 200;
  
  export function Navigator(start) {
    this.start = start;
  }
  
  Navigator.prototype.navigateTo = function (destination) {
    if (this.start === destination) return;
  
    this.start.animate('disable');
    setTimeout(() => {
      destination.animate('enable');
      destination.style.display = 'inline';
      this.start.style.display = 'none';
      this.start = destination;
    }, ANIMATION_TIME);
  };
  