07Stack-lift value toggle — when a detail value turns on, identical shape values stacked behind lift up in turn

<main class="stage">
<div class="sl is-demo" id="sl">
  <div class="sl__pile" id="slPile">
    <div class="sl__ghost" style="--n: 3"></div>
    <div class="sl__ghost" style="--n: 2"></div>
    <div class="sl__ghost" style="--n: 1"></div>
    <div class="sl__card">
      <span class="sl__title">Notification value bundle</span>
      <span class="sl__sub">3 values stacked behind</span>
    </div>
  </div>
  <button type="button" class="sl__btn" id="slBtn" aria-expanded="false">
    <span class="sl__label">Open detail value</span>
  </button>
</div>
</main>

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

// 계산 겹: 겹친 카드의 y 오프셋이 --n(뒤에서부터의 차례) * STEP_PX(34px) 산술로 결정되고,
// 들림은 $ease-lerp-settle 표본곡선(오버슈트 후 빠른 정착)으로 스프링 감쇠를 흉내낸다.
@include stage($stage-orange);

.sl {
  display: grid;
  gap: $sp-5;
  justify-items: center;
}

.sl__pile {
  position: relative;
  width: 230px;
  height: 118px;
}

.sl__ghost {
  position: absolute;
  inset: 0;
  border-radius: $r-card;
  background: rgba($stage-paper, .35);
  border: 1px solid rgba($stage-paper, .5);
  transform: translateY(calc((4 - var(--n)) * 4px));
  transition: transform $dur-enter $ease-lerp-settle;
}

.sl__card {
  position: absolute;
  inset: 0;
  border-radius: $r-card;
  background: $stage-paper;
  box-shadow: $shadow-raised;
  display: grid;
  align-content: center;
  gap: $sp-1;
  padding: 0 $sp-5;
  box-sizing: border-box;
}

.sl__title {
  color: $subject-ink;
  font-weight: 700;
  font-size: 15px;
}

.sl__sub {
  color: $subject-orange-deep;
  font-weight: 600;
  font-size: 12px;
}

.sl__btn {
  border: 0;
  border-radius: $r-pill;
  background: $stage-paper;
  color: $subject-ink;
  padding: $sp-2 $sp-5;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
}

.sl--open {
  .sl__ghost {
    transform: translateY(calc(-1 * var(--n) * 34px)) scale(calc(1 - var(--n) * .03));
  }
}

@media (max-width: 340px) {
  .sl__pile { width: 200px; height: 108px; }
}

@media (prefers-reduced-motion: reduce) {
  .sl__ghost { transition: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.sl {
  display: grid;
  gap: 20px;
  justify-items: center;
}

.sl__pile {
  position: relative;
  width: 230px;
  height: 118px;
}

.sl__ghost {
  position: absolute;
  inset: 0;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.5);
  transform: translateY(calc((4 - var(--n)) * 4px));
  transition: transform 600ms linear(0, 0.051, 0.176, 0.341, 0.518, 0.685, 0.831, 0.947, 1.032, 1.087, 1.117, 1.126, 1.121, 1.105, 1.085, 1.062, 1.041, 1.022, 1.008, 0.997, 1);
}

.sl__card {
  position: absolute;
  inset: 0;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  display: grid;
  align-content: center;
  gap: 4px;
  padding: 0 20px;
  box-sizing: border-box;
}

.sl__title {
  color: #17141a;
  font-weight: 700;
  font-size: 15px;
}

.sl__sub {
  color: #c93000;
  font-weight: 600;
  font-size: 12px;
}

.sl__btn {
  border: 0;
  border-radius: 999px;
  background: #ffffff;
  color: #17141a;
  padding: 8px 20px;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
}

.sl--open .sl__ghost {
  transform: translateY(calc(-1 * var(--n) * 34px)) scale(calc(1 - var(--n) * 0.03));
}

@media (max-width: 340px) {
  .sl__pile {
    width: 200px;
    height: 108px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .sl__ghost {
    transition: none;
  }
}

(function () {
  var root = document.getElementById('sl');
  var btn = document.getElementById('slBtn');
  var ghosts = root.querySelectorAll('.sl__ghost');
  var sub = root.querySelector('.sl__sub');
  var STEP_PX = 34; // 계산 겹: 겹침 카드 하나가 위로 들리는 y 오프셋(px) — 스프링 감쇠로 산출
  var STAGGER_MS = 80; // 계산 겹: 뒤 카드부터 이 값씩 늦게 들린다

  ghosts.forEach(function (g, i) {
    g.style.transitionDelay = ((ghosts.length - 1 - i) * STAGGER_MS) + 'ms';
  });

  var open = false;
  function paint() {
    root.classList.toggle('sl--open', open);
    btn.setAttribute('aria-expanded', String(open));
    sub.textContent = open ? '3 values expanded' : '3 values stacked behind';
  }

  function toggle() {
    open = !open;
    paint();
  }

  btn.addEventListener('click', function () {
    root.classList.remove('is-demo');
    stopAutoplay();
    toggle();
  });

  var autoTimer = null;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (!reduce) { autoTimer = setInterval(toggle, 1400); }
  else { open = true; paint(); }
})();

import { useEffect, useRef } from "react";
import type { CSSProperties } from "react";
import styles from "./StackCardLift.module.scss";

type Box<T> = { current: T };

const STEP_PX = 34; // 계산 겹: 겹침 카드 하나가 위로 들리는 y 오프셋(px) — 스프링 감쇠로 산출
const STAGGER_MS = 80; // 계산 겹: 뒤 카드부터 이 값씩 늦게 들린다

export default function StackCardLift() {
  const rootRef = useRef(null) as unknown as Box<HTMLDivElement | null>;

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const btn = root.querySelector(`.${styles.btn}`) as HTMLButtonElement | null;
    const ghosts = root.querySelectorAll(`.${styles.ghost}`);
    const sub = root.querySelector(`.${styles.sub}`) as HTMLElement | null;
    if (!btn) return;

    ghosts.forEach((g, i) => {
      (g as HTMLElement).style.transitionDelay = ((ghosts.length - 1 - i) * STAGGER_MS) + "ms";
    });

    let open = false;
    function paint() {
      root!.classList.toggle(styles["root--open"], open);
      btn!.setAttribute("aria-expanded", String(open));
      if (sub) sub.textContent = open ? "값 3개 펼침" : "뒤에 값 3개 겹침";
    }
    function toggle() {
      open = !open;
      paint();
    }

    function onClick() {
      root!.classList.remove(styles["is-demo"]);
      stopAutoplay();
      toggle();
    }
    btn.addEventListener("click", onClick);

    let autoTimer: number | null = null;
    function stopAutoplay() { if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; } }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (!reduce) { autoTimer = window.setInterval(toggle, 1400); }
    else { open = true; paint(); }

    return () => {
      stopAutoplay();
      btn.removeEventListener("click", onClick);
    };
  }, []);

  return (
    <div ref={rootRef} className={`${styles.stage} ${styles.sl} ${styles["is-demo"]}`}>
      <div className={styles.pile}>
        <div className={styles.ghost} style={{ "--n": 3 } as CSSProperties} />
        <div className={styles.ghost} style={{ "--n": 2 } as CSSProperties} />
        <div className={styles.ghost} style={{ "--n": 1 } as CSSProperties} />
        <div className={styles.card}>
          <span className={styles.title}>알림 값 묶음</span>
          <span className={styles.sub}>뒤에 값 3개 겹침</span>
        </div>
      </div>
      <button type="button" className={styles.btn} aria-expanded="false">
        <span className={styles.label}>자세히 값 열기</span>
      </button>
    </div>
  );
}