01Peek-next scroll-snap

<main class="stage">
  <div class="pn is-demo">
    <div class="pn__viewport">
      <div class="pn__track">
        <div class="pn__slide pn__slide--1"><span class="pn__cap">01</span></div>
        <div class="pn__slide pn__slide--2"><span class="pn__cap">02</span></div>
        <div class="pn__slide pn__slide--3"><span class="pn__cap">03</span></div>
        <div class="pn__slide pn__slide--4"><span class="pn__cap">04</span></div>
        <div class="pn__slide pn__slide--1" aria-hidden="true"><span class="pn__cap">01</span></div>
        <div class="pn__slide pn__slide--2" aria-hidden="true"><span class="pn__cap">02</span></div>
      </div>
    </div>
  </div>
</main>

@use "../../../../site/static/demo-tokens" as *;

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-base;
$easing: $ease-spring;
$color: $subject-blue;

@include stage($stage-ink);

.pn { width: min(360px, 88vw); }

// ── 실제 동작: overflow-x:auto + scroll-snap-type + scroll-padding-left (0줄 JS) ──
// 카드가 뷰포트의 78% 만 차지해 다음 카드가 22% 만큼 미리 보인다.
.pn__viewport {
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-padding-left: $sp-4;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  &::-webkit-scrollbar { display: none; }
}
.pn__track {
  display: flex;
  width: max-content;
}
.pn__slide {
  flex: 0 0 200px;
  aspect-ratio: 4 / 3;
  scroll-snap-align: start;
  margin-right: $sp-3;
  border-radius: $r-card;
  position: relative;
  overflow: hidden;
  display: grid;
  place-items: end start;
  box-sizing: border-box;
  &:last-child { margin-right: 0; }
}
.pn__slide--1 { background: linear-gradient(135deg, $color, #d6ddeb); }
.pn__slide--2 { background: linear-gradient(135deg, $stage-orange, #ebdbd6); }
.pn__slide--3 { background: linear-gradient(135deg, #c2ae82, $stage-yellow); }
.pn__slide--4 { background: linear-gradient(135deg, $subject-ink, #4a3f5c); }
.pn__cap {
  position: relative; z-index: 1;
  margin: $sp-4;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .85);
  color: $subject-ink;
  font-weight: 700;
  font-size: clamp(12px, 3.2vw, 14px);
  line-height: 1;
  font-family: inherit;
}

// ── 데모 루프: 클릭·드래그 전까지 한 칸씩 스스로 넘어간다 (진짜 스크롤은 그대로 살아있다) ──
// 트랙 끝에는 1번의 복제본(aria-hidden)이 한 장 더 — 그곳까지 정상 속도로 가고
// 100%→0% 점프는 복제본이 1번과 같아 안 보인다 (끝→처음 텔레포트 금지, 사용자 2026-09-11)
.pn.is-demo .pn__track { animation: pn-loop $dur-loop $easing infinite; }
@keyframes pn-loop {
  0%, 8%    { transform: translateX(0px); }
  23%, 31%  { transform: translateX(-212px); }
  46%, 54%  { transform: translateX(-424px); }
  69%, 77%  { transform: translateX(-636px); }
  92%, 100% { transform: translateX(-848px); }
}

// ── 접근성 ──────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .pn.is-demo .pn__track { animation: none !important; }
  .pn__viewport { scroll-behavior: auto; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.pn {
  width: min(360px, 88vw);
}

.pn__viewport {
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-padding-left: 16px;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.pn__viewport::-webkit-scrollbar {
  display: none;
}

.pn__track {
  display: flex;
  width: max-content;
}

.pn__slide {
  flex: 0 0 200px;
  aspect-ratio: 4/3;
  scroll-snap-align: start;
  margin-right: 12px;
  border-radius: 16px;
  position: relative;
  overflow: hidden;
  display: grid;
  place-items: end start;
  box-sizing: border-box;
}
.pn__slide:last-child {
  margin-right: 0;
}

.pn__slide--1 {
  background: linear-gradient(135deg, #2f6df6, #d6ddeb);
}

.pn__slide--2 {
  background: linear-gradient(135deg, #ff4d1f, #ebdbd6);
}

.pn__slide--3 {
  background: linear-gradient(135deg, #c2ae82, #ffd23f);
}

.pn__slide--4 {
  background: linear-gradient(135deg, #17141a, #4a3f5c);
}

.pn__cap {
  position: relative;
  z-index: 1;
  margin: 16px;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #17141a;
  font-weight: 700;
  font-size: clamp(12px, 3.2vw, 14px);
  line-height: 1;
  font-family: inherit;
}

.pn.is-demo .pn__track {
  animation: pn-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@keyframes pn-loop {
  0%, 8% {
    transform: translateX(0px);
  }
  23%, 31% {
    transform: translateX(-212px);
  }
  46%, 54% {
    transform: translateX(-424px);
  }
  69%, 77% {
    transform: translateX(-636px);
  }
  92%, 100% {
    transform: translateX(-848px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .pn.is-demo .pn__track {
    animation: none !important;
  }
  .pn__viewport {
    scroll-behavior: auto;
  }
}

// 실제 동작은 overflow-x:auto + scroll-snap-type + scroll-padding 만으로 끝난다(0줄).
// 이 3줄은 미리보기 자동 재생만 멈춘다 — 진짜 드래그·스크롤은 그대로 살아있다.
document.querySelector('.pn__viewport').addEventListener('pointerdown', function () {
  document.querySelector('.pn').classList.remove('is-demo');
});

import type { CSSProperties } from "react";
import styles from "./PeekNext.module.scss";

export type PeekNextProps = {
  duration?: number;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };

export default function PeekNext({ duration = 300, easing = "cubic-bezier(.2,.8,.2,1)", color = "#2f6df6" }: PeekNextProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  return (
    <div className={styles.pn} style={vars}>
      {/* 실제 동작은 overflow-x:auto + scroll-snap-type + scroll-padding-left 만으로 끝난다 — 0줄 JS */}
      <div className={styles.viewport}>
        <div className={styles.track}>
          {[1, 2, 3, 4].map((n) => (
            <div key={n} className={`${styles.slide} ${styles["slide" + n]}`}>
              <span className={styles.cap}>{String(n).padStart(2, "0")}</span>
            </div>
          ))}
        </div>
      </div>
    </div>
  );
}