06Page turn

<main class="stage">
  <div class="bp-book is-demo">
    <div class="bp-page-under">02</div>
    <div class="bp-page">
      <div class="bp-page__face bp-page__face--front">01</div>
      <div class="bp-page__face bp-page__face--back">01</div>
    </div>
  </div>
</main>

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

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

@include stage($stage-yellow);

.bp-book {
  position: relative;
  width: 150px;
  height: 108px;
  perspective: 900px;
}

.bp-page-under,
.bp-page__face {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: $r-card;
  font: 700 22px/1 -apple-system, "Segoe UI", sans-serif;
  color: $subject-ink;
}
.bp-page-under { background: $color; box-shadow: $shadow-press; }

.bp-page {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transform-origin: right center; // 규칙8: 오른쪽 책등 경첩 넘김
  transition: transform $duration $easing, box-shadow $duration $easing;
  border-radius: $r-card;
  box-shadow: $shadow-raised;
}
.bp-page__face { backface-visibility: hidden; }
.bp-page__face--front { background: $color; }
.bp-page__face--back { background: rgba(23, 20, 26, .78); color: $subject-cream; transform: rotateY(180deg); }

// 데모 루프: 오른쪽 끝을 축으로 페이지가 넘어간다
@keyframes bp-turn {
  0%, 30%  { transform: rotateY(0); }
  70%, 100% { transform: rotateY(-155deg); }
}
.bp-book.is-demo .bp-page { animation: bp-turn $duration * 2.6 $easing infinite; }

@media (prefers-reduced-motion: reduce) {
  .bp-book.is-demo .bp-page { animation: none !important; transition: 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: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.bp-book {
  position: relative;
  width: 150px;
  height: 108px;
  perspective: 900px;
}

.bp-page-under,
.bp-page__face {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 16px;
  font: 700 22px/1 -apple-system, "Segoe UI", sans-serif;
  color: #17141a;
}

.bp-page-under {
  background: #fff7e6;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

.bp-page {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transform-origin: right center;
  transition: transform 600ms cubic-bezier(0.2, 0.8, 0.2, 1), box-shadow 600ms cubic-bezier(0.2, 0.8, 0.2, 1);
  border-radius: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.bp-page__face {
  backface-visibility: hidden;
}

.bp-page__face--front {
  background: #fff7e6;
}

.bp-page__face--back {
  background: rgba(23, 20, 26, 0.78);
  color: #fff7e6;
  transform: rotateY(180deg);
}

@keyframes bp-turn {
  0%, 30% {
    transform: rotateY(0);
  }
  70%, 100% {
    transform: rotateY(-155deg);
  }
}
.bp-book.is-demo .bp-page {
  animation: bp-turn 1560ms cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@media (prefers-reduced-motion: reduce) {
  .bp-book.is-demo .bp-page {
    animation: none !important;
    transition: none !important;
    transform: none !important;
  }
}

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

export interface PageTurnProps {
  duration?: string;
  easing?: string;
  current?: string;
  next?: string;
}

export default function PageTurn({
  duration = "600ms",
  easing = "cubic-bezier(.2, .8, .2, 1)",
  current = "01",
  next = "02",
}: PageTurnProps) {
  const [turned, setTurned] = useState(false);
  const style = { "--duration": duration, "--easing": easing } as CSSProperties;
  return (
    <div
      className={styles.book}
      style={style}
      role="button"
      tabIndex={0}
      aria-pressed={turned}
      onClick={() => setTurned((v) => !v)}
      onKeyDown={(e: { key: string }) => (e.key === "Enter" || e.key === " ") && setTurned((v) => !v)}
    >
      <div className={styles.under}>{next}</div>
      <div className={`${styles.page} ${turned ? styles.turned : ""}`}>
        <div className={`${styles.face} ${styles.front}`}>{current}</div>
        <div className={`${styles.face} ${styles.back}`}>{current}</div>
      </div>
    </div>
  );
}