Pinned Horizontal Gallery

[hidden] {
  display: none !important;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: #08080c;
  color: #eee;
}

.intro,
.outro {
  min-height: 60vh;
  display: grid;
  place-content: center;
  padding: 2rem;
  text-align: center;
}

.intro h1 {
  margin: 0 0 0.5rem;
  font-size: clamp(1.75rem, 4vw, 2.5rem);
}

.intro p,
.outro p {
  margin: 0;
  color: #888;
}

.pin-wrap {
  height: 100vh;
}

.pin-viewport {
  height: 100vh;
  overflow: hidden;
  background: #0f0f14;
}

.track {
  display: flex;
  height: 100%;
  width: max-content;
  will-change: transform;
}

.slide {
  position: relative;
  flex: 0 0 100vw;
  height: 100%;
  padding: 2rem;
  display: grid;
  place-items: center;
}

.slide img {
  width: min(72vw, 720px);
  height: min(52vh, 480px);
  object-fit: cover;
  border-radius: 12px;
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.5);
}

.slide span {
  position: absolute;
  bottom: 3rem;
  left: 3rem;
  font-size: 0.75rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: #aaa;
}

const reduced = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
const track = document.querySelector(".track");
const slides = document.querySelectorAll(".slide");

gsap.registerPlugin(ScrollTrigger);

function setupHorizontal() {
  const totalScroll = track.scrollWidth - window.innerWidth;
  if (totalScroll <= 0) return;

  gsap.to(track, {
    x: () => -totalScroll,
    ease: "none",
    scrollTrigger: {
      trigger: ".pin-wrap",
      start: "top top",
      end: () => `+=${totalScroll}`,
      pin: ".pin-viewport",
      scrub: reduced ? false : 0.8,
      invalidateOnRefresh: true,
    },
  });
}

function bootLenis() {
  if (reduced || typeof Lenis === "undefined") {
    setupHorizontal();
    ScrollTrigger.refresh();
    return;
  }
  const lenis = new Lenis({ autoRaf: false });
  lenis.on("scroll", ScrollTrigger.update);
  gsap.ticker.add((t) => lenis.raf(t * 1000));
  gsap.ticker.lagSmoothing(0);
  setupHorizontal();
  ScrollTrigger.refresh();
}

bootLenis();

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Pinned Horizontal Gallery</title>
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <section class="intro">
      <h1>Scroll vertically</h1>
      <p>The gallery moves sideways while this block stays pinned.</p>
    </section>

    <section class="pin-wrap">
      <div class="pin-viewport">
        <div class="track">
          <article class="slide"><img src="https://images.unsplash.com/photo-1500530855697-b586d89ba3ee?w=900&q=80" alt="" /><span>Mist</span></article>
          <article class="slide"><img src="https://images.unsplash.com/photo-1501785888041-af3ef285b470?w=900&q=80" alt="" /><span>Alpine</span></article>
          <article class="slide"><img src="https://images.unsplash.com/photo-1491553895911-0055eca6402d?w=900&q=80" alt="" /><span>Coast</span></article>
          <article class="slide"><img src="https://images.unsplash.com/photo-1519681393784-d120267933ba?w=900&q=80" alt="" /><span>Peaks</span></article>
          <article class="slide"><img src="https://images.unsplash.com/photo-1507525428034-b723cf961d3e?w=900&q=80" alt="" /><span>Surf</span></article>
        </div>
      </div>
    </section>

    <section class="outro">
      <p>End of gallery — keep scrolling.</p>
    </section>

    <script src="https://cdn.jsdelivr.net/npm/gsap@3.12.5/dist/gsap.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/gsap@3.12.5/dist/ScrollTrigger.min.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/lenis@1.1.18/dist/lenis.min.js"></script>
    <script src="script.js"></script>
  </body>
</html>