(() => {
  "use strict";

  const elements = Array.from(
    document.querySelectorAll(".reveal-up, .reveal-left, .reveal-right, .reveal-scale")
  );

  if (!elements.length) return;

  const reducedMotion = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

  elements.forEach((element, index) => {
    const group = element.closest(".row, .stats-row, section") || document.body;
    const peers = Array.from(
      group.querySelectorAll(":scope > .reveal-up, :scope > .reveal-left, :scope > .reveal-right, :scope > .reveal-scale")
    );
    const peerIndex = Math.max(0, peers.indexOf(element));
    element.style.transitionDelay = `${Math.min(peerIndex, 4) * 70}ms`;
    element.dataset.revealIndex = String(index);
  });

  const reveal = (element) => element.classList.add("is-visible");

  if (reducedMotion || !("IntersectionObserver" in window)) {
    elements.forEach(reveal);
    return;
  }

  const observer = new IntersectionObserver(
    (entries, currentObserver) => {
      entries.forEach((entry) => {
        if (!entry.isIntersecting) return;
        reveal(entry.target);
        currentObserver.unobserve(entry.target);
      });
    },
    { rootMargin: "0px 0px -9%", threshold: 0.08 }
  );

  elements.forEach((element) => observer.observe(element));

  // The hero must never remain hidden while the page initializes.
  document.querySelectorAll(".hero-section .reveal-up, .hero-section .reveal-scale").forEach(reveal);
})();