/* MOONARC — scroll reveal + sticky-header state (proof) */
(function () {
	'use strict';
	var body = document.body;
	body.classList.add('moonarc-js');

	var selectors = [
		'.moonarc-hero__inner',
		'.moonarc-head',
		'.moonarc-card',
		'.moonarc-reason',
		'.moonarc-faq details',
		'.moonarc-cta__inner'
	];
	var els = Array.prototype.slice.call(document.querySelectorAll(selectors.join(',')));

	// stagger: 同じ親の中での出現順にわずかな遅延
	els.forEach(function (el) {
		var siblings = Array.prototype.slice.call(el.parentNode.children).filter(function (n) {
			return n.classList && (
				n.classList.contains('moonarc-card') ||
				n.classList.contains('moonarc-reason')
			);
		});
		var idx = siblings.indexOf(el);
		if (idx > 0) { el.style.transitionDelay = (idx * 70) + 'ms'; }
	});

	if (!('IntersectionObserver' in window) || !els.length) {
		els.forEach(function (el) { el.classList.add('is-revealed'); });
		return;
	}

	var io = new IntersectionObserver(function (entries) {
		entries.forEach(function (en) {
			if (en.isIntersecting) {
				en.target.classList.add('is-revealed');
				io.unobserve(en.target);
			}
		});
	}, { threshold: 0.12, rootMargin: '0px 0px -8% 0px' });

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

	// sticky header: スクロールで背景を濃く
	var header = document.querySelector('.moonarc-header');
	if (header) {
		var onScroll = function () {
			header.classList.toggle('is-stuck', window.scrollY > 12);
		};
		onScroll();
		window.addEventListener('scroll', onScroll, { passive: true });
	}
})();