script.js

// Zetra site interactions: mobile nav, scroll reveal, footer year.
(function () {
  "use strict";

  // Mobile nav toggle
  var toggle = document.querySelector(".nav-toggle");
  var links = document.getElementById("nav-links");
  if (toggle && links) {
    toggle.addEventListener("click", function () {
      var open = links.classList.toggle("open");
      toggle.setAttribute("aria-expanded", open ? "true" : "false");
    });
    links.addEventListener("click", function (e) {
      if (e.target.tagName === "A") {
        links.classList.remove("open");
        toggle.setAttribute("aria-expanded", "false");
      }
    });
  }

  // Reveal on scroll
  var revealEls = document.querySelectorAll(".reveal");
  if ("IntersectionObserver" in window && revealEls.length) {
    var observer = new IntersectionObserver(
      function (entries) {
        entries.forEach(function (entry) {
          if (entry.isIntersecting) {
            entry.target.classList.add("visible");
            observer.unobserve(entry.target);
          }
        });
      },
      { threshold: 0.12 }
    );
    revealEls.forEach(function (el) { observer.observe(el); });
  } else {
    revealEls.forEach(function (el) { el.classList.add("visible"); });
  }

  // Footer year
  var year = document.getElementById("year");
  if (year) year.textContent = new Date().getFullYear();

  // Header shadow on scroll
  var header = document.getElementById("site-header");
  function onScroll() {
    if (window.scrollY > 8) {
      header.style.boxShadow = "0 8px 24px rgba(0,0,0,0.35)";
    } else {
      header.style.boxShadow = "none";
    }
  }
  window.addEventListener("scroll", onScroll, { passive: true });
  onScroll();
})();