Cinematic Scroll Storytelling

function initPreloader() {
  const loader = document.querySelector("[data-preloader]");
  const bar = document.querySelector("[data-preloader-bar]");
  if (!loader) return Promise.resolve();

  if (reduceMotion) {
    loader.remove();
    return Promise.resolve();
  }

  return new Promise((resolve) => {
    const tl = gsap.timeline({
      defaults: { ease: "power3.out" },
      onComplete: () => {
        loader.remove();
        resolve();
      },
    });

    tl.fromTo(bar, { scaleX: 0, transformOrigin: "left" }, { scaleX: 1, duration: 1.1 })
      .to(loader, { yPercent: -100, duration: 0.9, ease: "power4.inOut" }, "+=0.15");
  });
}

function splitWords(element) {
  if (element.dataset.splitReady === "true") return;

  const text = element.textContent || "";
  const parts = text.split(/(\s+)/);
  element.textContent = "";
  element.setAttribute("aria-label", text.trim());

  parts.forEach((part) => {
    if (!part.trim()) {
      element.appendChild(document.createTextNode(part));
      return;
    }

    const mask = document.createElement("span");
    const word = document.createElement("span");
    mask.className = "split-word-mask";
    word.className = "split-word";
    word.textContent = part;
    mask.setAttribute("aria-hidden", "true");
    mask.appendChild(word);
    element.appendChild(mask);
  });

  element.dataset.splitReady = "true";
}

function initSplitReveals() {
  if (reduceMotion) {
    gsap.set("[data-split-reveal]", { autoAlpha: 1 });
    return;
  }

  gsap.utils.toArray("[data-split-reveal]").forEach((element) => {
    splitWords(element);
    const words = element.querySelectorAll(".split-word");

    gsap.fromTo(
      words,
      { yPercent: 110, autoAlpha: 0, filter: "blur(8px)" },
      {
        yPercent: 0,
        autoAlpha: 1,
        filter: "blur(0px)",
        duration: 0.95,
        ease: "power4.out",
        stagger: 0.05,
        scrollTrigger: {
          trigger: element,
          start: "top 82%",
          once: true,
        },
      }
    );
  });
}

.split-word-mask {
  display: inline-block;
  overflow: hidden;
  vertical-align: top;
}

.split-word {
  display: inline-block;
  will-change: transform, opacity, filter;
}

function initSectionReveals() {
  if (reduceMotion) {
    gsap.set("[data-story-section], [data-reveal-item]", { autoAlpha: 1, clearProps: "all" });
    return;
  }

  gsap.utils.toArray("[data-story-section]").forEach((section) => {
    const items = section.querySelectorAll("[data-reveal-item]");
    const targets = items.length ? items : section.children;

    gsap.fromTo(
      targets,
      { y: 36, autoAlpha: 0, filter: "blur(8px)" },
      {
        y: 0,
        autoAlpha: 1,
        filter: "blur(0px)",
        duration: 1,
        ease: "power4.out",
        stagger: 0.08,
        scrollTrigger: {
          trigger: section,
          start: "top 82%",
          once: true,
        },
      }
    );
  });
}

function initProgressionScenes() {
  if (reduceMotion) return;

  gsap.utils.toArray("[data-progress-scene]").forEach((scene) => {
    const media = scene.querySelector("[data-progress-media]");
    const copy = scene.querySelectorAll("[data-progress-copy]");

    gsap.timeline({
      scrollTrigger: {
        trigger: scene,
        start: "top top",
        end: "+=140%",
        scrub: 1.1,
        pin: true,
        anticipatePin: 1,
      },
    })
      .fromTo(media, { scale: 1.08 }, { scale: 1, ease: "none" })
      .fromTo(copy, { autoAlpha: 0, y: 40 }, { autoAlpha: 1, y: 0, stagger: 0.15, ease: "none" }, 0.15);
  });
}

[data-sticky-stack] {
  position: relative;
}

[data-stack-card] {
  position: sticky;
  top: 12vh;
  transform-origin: center top;
  will-change: transform, opacity;
}

function initStickyCardStack() {
  if (reduceMotion) return;

  gsap.utils.toArray("[data-sticky-stack]").forEach((stack) => {
    const cards = gsap.utils.toArray(stack.querySelectorAll("[data-stack-card]"));

    cards.forEach((card, index) => {
      const nextCard = cards[index + 1];
      if (!nextCard) return;

      gsap.to(card, {
        scale: 0.92 + index * 0.015,
        autoAlpha: 0.72,
        y: -24,
        ease: "none",
        scrollTrigger: {
          trigger: nextCard,
          start: "top 78%",
          end: "top 24%",
          scrub: true,
          invalidateOnRefresh: true,
        },
      });
    });
  });
}

function initParallax() {
  if (reduceMotion) return;

  gsap.utils.toArray("[data-parallax-layer]").forEach((layer) => {
    const speed = Number(layer.dataset.speed || -0.16);
    const section = layer.closest("[data-parallax-section]") || layer;

    gsap.to(layer, {
      y: () => window.innerHeight * speed,
      ease: "none",
      scrollTrigger: {
        trigger: section,
        start: "top bottom",
        end: "bottom top",
        scrub: 1,
        invalidateOnRefresh: true,
      },
    });
  });
}

function initFooterReveal() {
  if (reduceMotion) return;

  const footer = document.querySelector("[data-footer-parallax]");
  if (!footer) return;

  gsap.fromTo(
    footer,
    { yPercent: -12, autoAlpha: 0.85 },
    {
      yPercent: 0,
      autoAlpha: 1,
      ease: "none",
      scrollTrigger: {
        trigger: footer,
        start: "top bottom",
        end: "top 45%",
        scrub: 1,
      },
    }
  );
}

Create a cinematic scroll-driven landing page with smooth Lenis scrolling, GSAP ScrollTrigger animations, staggered text reveals, sticky card stack progression, parallax backgrounds, scroll-scrubbed transitions, section-by-section storytelling, and an immersive preloader animation. Use layered depth, scaling transitions, progressive opacity changes, and smooth viewport-triggered motion for a premium editorial experience.