Lenis Smooth Scroll

[hidden] {
  display: none !important;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: auto;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  background: #0a0a0f;
  color: #e8e6f0;
  line-height: 1.5;
}

.hero {
  min-height: 100vh;
  display: grid;
  place-content: center;
  padding: 2rem;
  text-align: center;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, #1a1530 0%, #0a0a0f 70%);
}

.eyebrow {
  margin: 0 0 0.75rem;
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: #9b8cff;
}

.hero h1 {
  margin: 0 0 1rem;
  font-size: clamp(2rem, 5vw, 3.25rem);
  font-weight: 600;
  letter-spacing: -0.03em;
}

.lede {
  margin: 0 auto;
  max-width: 32rem;
  color: #a8a4b8;
}

code {
  font-size: 0.9em;
  color: #c4b8ff;
}

.panel {
  min-height: 90vh;
  display: grid;
  place-items: center;
  padding: 4rem 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.panel--accent {
  background: linear-gradient(180deg, #12101a 0%, #0a0a0f 100%);
}

.panel-inner {
  max-width: 28rem;
  opacity: 0;
  transform: translateY(48px);
}

.num {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.8rem;
  color: #6b6578;
}

.panel h2 {
  margin: 0 0 0.75rem;
  font-size: 1.75rem;
  letter-spacing: -0.02em;
}

.panel p {
  margin: 0;
  color: #a8a4b8;
}

.outro {
  padding: 4rem 1.5rem 6rem;
  text-align: center;
  color: #6b6578;
  font-size: 0.875rem;
}

const reduced = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

gsap.registerPlugin(ScrollTrigger);

function initPanels() {
  document.querySelectorAll("[data-panel] .panel-inner").forEach((el) => {
    if (reduced) {
      gsap.set(el, { opacity: 1, y: 0 });
      return;
    }
    gsap.fromTo(
      el,
      { opacity: 0, y: 48 },
      {
        opacity: 1,
        y: 0,
        duration: 0.9,
        ease: "power3.out",
        scrollTrigger: {
          trigger: el.closest("[data-panel]"),
          start: "top 75%",
          end: "top 40%",
          scrub: 0.6,
        },
      }
    );
  });
}

if (reduced || typeof Lenis === "undefined") {
  initPanels();
  ScrollTrigger.refresh();
} else {
  const lenis = new Lenis({ duration: 1.1, smoothWheel: true, autoRaf: false });

  lenis.on("scroll", ScrollTrigger.update);

  gsap.ticker.add((time) => {
    lenis.raf(time * 1000);
  });
  gsap.ticker.lagSmoothing(0);

  ScrollTrigger.scrollerProxy(document.documentElement, {
    scrollTop(value) {
      if (arguments.length) {
        lenis.scrollTo(value, { immediate: true });
      }
      return lenis.scroll;
    },
    getBoundingClientRect() {
      return {
        top: 0,
        left: 0,
        width: window.innerWidth,
        height: window.innerHeight,
      };
    },
  });

  initPanels();
  ScrollTrigger.addEventListener("refresh", () => lenis.resize());
  ScrollTrigger.refresh();
}

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Lenis Smooth Scroll</title>
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <header class="hero">
      <p class="eyebrow">Lenis + ScrollTrigger</p>
      <h1>Smooth scroll that still scrubs</h1>
      <p class="lede">Scroll down — motion stays tied to Lenis via <code>scrollerProxy</code>.</p>
    </header>

    <section class="panel" data-panel>
      <div class="panel-inner">
        <span class="num">01</span>
        <h2>Momentum without drift</h2>
        <p>Wheel input eases out; ScrollTrigger reads the same scroll position Lenis animates.</p>
      </div>
    </section>
    <section class="panel panel--accent" data-panel>
      <div class="panel-inner">
        <span class="num">02</span>
        <h2>Proxy the scroller</h2>
        <p>Map <code>scrollTop</code> to <code>lenis.scroll</code> so pins and scrub timelines stay aligned.</p>
      </div>
    </section>
    <section class="panel" data-panel>
      <div class="panel-inner">
        <span class="num">03</span>
        <h2>Reduced motion</h2>
        <p>When users prefer less motion, Lenis is skipped and content is fully visible.</p>
      </div>
    </section>

    <footer class="outro">
      <p>StealThis · Lenis smooth scroll demo</p>
    </footer>

    <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>