/* ============================================================
   ZS RECYCLING — Process Steps Scroll Animations
   ============================================================ */

(function () {
  'use strict';

  if (!('IntersectionObserver' in window)) {
    // Fallback: show all steps immediately
    document.querySelectorAll('.process-step, .process-step-card').forEach(function (el) {
      el.classList.add('visible');
    });
    return;
  }

  // ---- Timeline steps (vertical single-column) ----
  var stepEls = document.querySelectorAll('.process-step');
  if (stepEls.length > 0) {
    var stepObserver = new IntersectionObserver(function (entries) {
      entries.forEach(function (entry) {
        if (entry.isIntersecting) {
          entry.target.classList.add('visible');
          stepObserver.unobserve(entry.target);
        }
      });
    }, { threshold: 0.2, rootMargin: '0px 0px -60px 0px' });

    stepEls.forEach(function (el) { stepObserver.observe(el); });
  }

  // ---- Step cards (2-column grid) ----
  var cardEls = document.querySelectorAll('.process-step-card');
  if (cardEls.length > 0) {
    var cardObserver = new IntersectionObserver(function (entries) {
      entries.forEach(function (entry) {
        if (entry.isIntersecting) {
          entry.target.classList.add('visible');
          cardObserver.unobserve(entry.target);
        }
      });
    }, { threshold: 0.15, rootMargin: '0px 0px -40px 0px' });

    cardEls.forEach(function (el, i) {
      el.style.transitionDelay = (i * 0.12) + 's';
      cardObserver.observe(el);
    });
  }
})();