05Shuffle a stack

<main class="stage">
  <div class="ss-stack is-demo">
    <div class="ss-card ss-card--3">★★★☆☆</div>
    <div class="ss-card ss-card--2">★★★★☆</div>
    <div class="ss-card ss-card--1">★★★★★</div>
  </div>
</main>

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

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

@include stage($stage-ink);

.ss-stack {
  position: relative;
  width: 150px;
  height: 92px;
  perspective: 700px;
}

.ss-card {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: $r-card;
  background: $color;
  color: $subject-ink;
  font: 700 16px/1 -apple-system, "Segoe UI", sans-serif;
  box-shadow: $shadow-raised;
  transform-style: preserve-3d;
}

// 아래 두 장은 살짝 물러나 쌓여 보인다 (translateZ + translateY)
.ss-card--2 { transform: translateZ(-16px) translateY($sp-2); opacity: .85; }
.ss-card--3 { transform: translateZ(-32px) translateY($sp-4); opacity: .65; }

// 데모 루프: 맨 위 카드(1번, z-index 최상)가 뒤집히며 물러나 다음 카드를 드러낸다
@keyframes ss-shuffle {
  0%, 30%  { transform: translateZ(0) translateX(0) rotateY(0); opacity: 1; }
  70%      { transform: translateZ(-8px) translateX(-46px) rotateY(-150deg); opacity: .25; }
  71%, 100% { transform: translateZ(0) translateX(0) rotateY(0); opacity: 1; }
}
.ss-stack.is-demo .ss-card--1 { z-index: 3; animation: ss-shuffle ($duration * 6) $easing infinite; }

@media (prefers-reduced-motion: reduce) {
  .ss-stack.is-demo .ss-card--1 { animation: none !important; transform: none !important; }
}

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);
}

.ss-stack {
  position: relative;
  width: 150px;
  height: 92px;
  perspective: 700px;
}

.ss-card {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 16px;
  background: #fff7e6;
  color: #17141a;
  font: 700 16px/1 -apple-system, "Segoe UI", sans-serif;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform-style: preserve-3d;
}

.ss-card--2 {
  transform: translateZ(-16px) translateY(8px);
  opacity: 0.85;
}

.ss-card--3 {
  transform: translateZ(-32px) translateY(16px);
  opacity: 0.65;
}

@keyframes ss-shuffle {
  0%, 30% {
    transform: translateZ(0) translateX(0) rotateY(0);
    opacity: 1;
  }
  70% {
    transform: translateZ(-8px) translateX(-46px) rotateY(-150deg);
    opacity: 0.25;
  }
  71%, 100% {
    transform: translateZ(0) translateX(0) rotateY(0);
    opacity: 1;
  }
}
.ss-stack.is-demo .ss-card--1 {
  z-index: 3;
  animation: ss-shuffle 1800ms cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@media (prefers-reduced-motion: reduce) {
  .ss-stack.is-demo .ss-card--1 {
    animation: none !important;
    transform: none !important;
  }
}

import { CSSProperties, useState } from "react";
import styles from "./StackShuffle.module.scss";

export interface StackShuffleProps {
  duration?: string;
  easing?: string;
  cards?: string[];
}

export default function StackShuffle({
  duration = "300ms",
  easing = "cubic-bezier(.2, .8, .2, 1)",
  cards = ["★★★★★", "★★★★☆", "★★★☆☆"],
}: StackShuffleProps) {
  const [order, setOrder] = useState(cards);
  const style = { "--duration": duration, "--easing": easing } as CSSProperties;
  const shuffle = () => setOrder((o) => [...o.slice(1), o[0]]);
  return (
    <div className={styles.stack} style={style} onClick={shuffle}>
      {order.map((text, i) => (
        <div
          key={text}
          className={`${styles.card} ${i === 0 ? styles.top : ""}`}
          style={{ transform: `translateZ(${-16 * i}px) translateY(${8 * i}px)`, opacity: 1 - i * 0.18 }}
        >
          {text}
        </div>
      ))}
    </div>
  );
}