08Autoplay hero with Ken Burns zoom

<main class="stage">
  <div class="kb">
    <div class="kb__stage">
      <div class="kb__card kb__card--1"><div class="kb__img kb__img--1"></div></div>
      <div class="kb__card kb__card--2"><div class="kb__img kb__img--2"></div></div>
      <div class="kb__card kb__card--3"><div class="kb__img kb__img--3"></div></div>
    </div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-base;
$easing: $ease-out;
$color: $stage-orange;

@include stage($stage-paper);

.kb { width: min(360px, 80vw); }

// ── 실제 동작: 카드가 같은 자리에서 오파시티로 교차되고, 보이는 카드의 배경만 계속 확대된다 (0줄 JS) ──
.kb__stage {
  display: grid;
  aspect-ratio: 16 / 10;
  border-radius: $r-card;
  overflow: hidden;
}
.kb__card { grid-area: 1 / 1; overflow: hidden; }
.kb__img { width: 100%; height: 100%; }
.kb__img--1 { background: radial-gradient(120% 120% at 30% 20%, $subject-blue, #14264d); }
.kb__img--2 { background: radial-gradient(120% 120% at 70% 30%, $color, #4a1c0d); }
.kb__img--3 { background: radial-gradient(120% 120% at 50% 70%, #c2ae82, #3a2a05); }

.kb__card--1 { animation: kb-fade-1 $dur-loop linear infinite; }
.kb__card--2 { animation: kb-fade-2 $dur-loop linear infinite; }
.kb__card--3 { animation: kb-fade-3 $dur-loop linear infinite; }
.kb__img--1  { animation: kb-zoom-1 $dur-loop $easing infinite; }
.kb__img--2  { animation: kb-zoom-2 $dur-loop $easing infinite; }
.kb__img--3  { animation: kb-zoom-3 $dur-loop $easing infinite; }

// 교차 페이드 창을 12% 로 넓게 — 마지막→처음 순간의 팝 없이 3번 페이드아웃(88→100%)과
// 1번 페이드인(0→12%)이 릴레이로 이어진다 (끝→처음 텔레포트 금지)
@keyframes kb-fade-1 { 0% { opacity: 0; } 12%, 25% { opacity: 1; } 37%, 100% { opacity: 0; } }
@keyframes kb-fade-2 { 0%, 25% { opacity: 0; } 37%, 58% { opacity: 1; } 70%, 100% { opacity: 0; } }
@keyframes kb-fade-3 { 0%, 58% { opacity: 0; } 70%, 88% { opacity: 1; } 100% { opacity: 0; } }

// 보이는 동안에만 천천히 확대되고, 다음 차례가 오면 다시 배율 1로 되돌아가 있다 (켄번즈 줌)
@keyframes kb-zoom-1 { 0% { transform: scale(1); } 29% { transform: scale(1.16); } 29.1%, 100% { transform: scale(1); } }
@keyframes kb-zoom-2 { 0%, 33% { transform: scale(1); } 62% { transform: scale(1.16); } 62.1%, 100% { transform: scale(1); } }
@keyframes kb-zoom-3 { 0%, 66% { transform: scale(1); } 96% { transform: scale(1.16); } }

// ── 접근성 ──────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .kb__card, .kb__img { animation: none !important; }
  .kb__card--1 { opacity: 1; }
  .kb__card--2, .kb__card--3 { opacity: 0; }
}

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

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

.kb {
  width: min(360px, 80vw);
}

.kb__stage {
  display: grid;
  aspect-ratio: 16/10;
  border-radius: 16px;
  overflow: hidden;
}

.kb__card {
  grid-area: 1/1;
  overflow: hidden;
}

.kb__img {
  width: 100%;
  height: 100%;
}

.kb__img--1 {
  background: radial-gradient(120% 120% at 30% 20%, #2f6df6, #14264d);
}

.kb__img--2 {
  background: radial-gradient(120% 120% at 70% 30%, #ff4d1f, #4a1c0d);
}

.kb__img--3 {
  background: radial-gradient(120% 120% at 50% 70%, #c2ae82, #3a2a05);
}

.kb__card--1 {
  animation: kb-fade-1 2s linear infinite;
}

.kb__card--2 {
  animation: kb-fade-2 2s linear infinite;
}

.kb__card--3 {
  animation: kb-fade-3 2s linear infinite;
}

.kb__img--1 {
  animation: kb-zoom-1 2s ease-out infinite;
}

.kb__img--2 {
  animation: kb-zoom-2 2s ease-out infinite;
}

.kb__img--3 {
  animation: kb-zoom-3 2s ease-out infinite;
}

@keyframes kb-fade-1 {
  0% {
    opacity: 0;
  }
  12%, 25% {
    opacity: 1;
  }
  37%, 100% {
    opacity: 0;
  }
}
@keyframes kb-fade-2 {
  0%, 25% {
    opacity: 0;
  }
  37%, 58% {
    opacity: 1;
  }
  70%, 100% {
    opacity: 0;
  }
}
@keyframes kb-fade-3 {
  0%, 58% {
    opacity: 0;
  }
  70%, 88% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}
@keyframes kb-zoom-1 {
  0% {
    transform: scale(1);
  }
  29% {
    transform: scale(1.16);
  }
  29.1%, 100% {
    transform: scale(1);
  }
}
@keyframes kb-zoom-2 {
  0%, 33% {
    transform: scale(1);
  }
  62% {
    transform: scale(1.16);
  }
  62.1%, 100% {
    transform: scale(1);
  }
}
@keyframes kb-zoom-3 {
  0%, 66% {
    transform: scale(1);
  }
  96% {
    transform: scale(1.16);
  }
}
@media (prefers-reduced-motion: reduce) {
  .kb__card, .kb__img {
    animation: none !important;
  }
  .kb__card--1 {
    opacity: 1;
  }
  .kb__card--2, .kb__card--3 {
    opacity: 0;
  }
}

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

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

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

export default function AutoplayKenburns({ duration = 6000, easing = "ease-out", color = "#ff4d1f" }: AutoplayKenburnsProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  return (
    <div className={styles.kb} style={vars}>
      {/* 카드가 같은 자리에서 오파시티로 교차되고, 보이는 카드의 배경만 계속 확대된다 — 0줄 JS */}
      <div className={styles.stageBox}>
        {[1, 2, 3].map((n) => (
          <div key={n} className={`${styles.card} ${styles["card" + n]}`}>
            <div className={`${styles.img} ${styles["img" + n]}`} />
          </div>
        ))}
      </div>
    </div>
  );
}