// Fade-in on scroll for elements with .reveal
(function () {
  var items = document.querySelectorAll(".reveal");
  if (!items.length) return;

  var show = function (el) { el.classList.add("is-visible"); };

  if (!("IntersectionObserver" in window)) {
    items.forEach(show);
    return;
  }

  // small stagger for siblings inside the same container
  var groups = new Map();
  items.forEach(function (el) {
    var parent = el.parentElement;
    var n = groups.get(parent) || 0;
    el.style.setProperty("--delay", n * 120 + "ms");
    groups.set(parent, n + 1);
  });

  var io = new IntersectionObserver(function (entries) {
    entries.forEach(function (entry) {
      if (!entry.isIntersecting) return;
      show(entry.target);
      io.unobserve(entry.target);
    });
  }, { threshold: 0.15, rootMargin: "0px 0px -8% 0px" });

  items.forEach(function (el) { io.observe(el); });
})();