05Background image zoom

<main class="stage">
  <div class="frame">
    <article class="card is-demo" tabindex="0">
      <span class="card__bg" aria-hidden="true">
        <span class="card__sun"></span>
        <span class="card__hill"></span>
      </span>
      <div class="card__overlay">
        <h3 class="card__title">Jeju Sea</h3>
        <p class="card__meta">Travel review</p>
      </div>
    </article>
  </div>
</main>

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

$duration: $dur-enter;                                // 배경이 다 커지는 시간
$easing: $ease-out;
$color: $subject-cream;

@include stage($stage-ink);
.stage { padding: clamp(6px, 2.4vw, 16px); }

@property --mx { syntax: "<percentage>"; inherits: true; initial-value: 50%; }
@property --my { syntax: "<percentage>"; inherits: true; initial-value: 50%; }
@property --sp { syntax: "<number>"; inherits: true; initial-value: 0; }
@property --rx { syntax: "<angle>"; inherits: true; initial-value: 0deg; }
@property --ry { syntax: "<angle>"; inherits: true; initial-value: 0deg; }

.frame { perspective: 700px; }                          // 커서 틸트가 이 값 기준으로 기운다

.card {
  position: relative;
  width: min(150px, 48vw);
  aspect-ratio: 4 / 3;
  border-radius: $r-card;
  overflow: hidden;                                    // 확대된 배경이 둥근 모서리 밖으로 안 나가게
  box-shadow: $shadow-raised;
  outline: none;
  cursor: pointer;
  transform: rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg));
  transition: transform $duration $easing;
}
.card::after {
  content: '';
  position: absolute; inset: 0; border-radius: inherit; pointer-events: none;
  background: radial-gradient(120px circle at var(--mx) var(--my), rgba(255,255,255,.32), transparent 70%);
  opacity: var(--sp);
}
.card__bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: linear-gradient(155deg, $subject-blue 0%, $color 100%);
  transform: scale(1);
  transition: transform $duration $easing;
}
.card__sun {
  position: absolute;
  top: 14%;
  right: 16%;
  width: 26%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: $stage-yellow;
}
.card__hill {
  position: absolute;
  left: -10%;
  right: -10%;
  bottom: -12%;
  height: 46%;
  border-radius: 50% 50% 0 0 / 100% 100% 0 0;
  background: $stage-ink;
  opacity: .85;
}
.card__overlay {
  position: absolute;
  z-index: 1;                                          // 스포트라이트(::after) 위로 올라오게
  left: 0; right: 0; bottom: 0;
  padding: 8px 12px;
  background: linear-gradient(to top, rgba($stage-ink, .78), transparent);
}
.card__title { margin: 0 0 2px; font-weight: 700; font-size: clamp(12px, 3.4vw, 14px); line-height: 1.3; font-family: inherit; color: $stage-paper; }
.card__meta { margin: 0; font-weight: 500; font-size: clamp(11px, 3vw, 12px); line-height: 1.3; font-family: inherit; color: rgba($stage-paper, .8); }

.card:hover .card__bg,
.card:focus-visible .card__bg,
.card:active .card__bg,
.card.is-demo .card__bg {
  transform: scale(1.12);
}
.card.is-demo .card__bg { animation: zoom-loop $dur-loop $ease-spring infinite; }
.card.is-demo { animation: tilt-loop $dur-loop $easing infinite, spot-loop $dur-loop $easing infinite; }

@keyframes zoom-loop {
  0%, 20%  { transform: scale(1); }
  50%, 75% { transform: scale(1.12); }
  100%     { transform: scale(1); }
}
@keyframes tilt-loop {
  0%, 15%   { --rx: 0deg; --ry: 0deg; }
  35%       { --rx: -4deg; --ry: 5deg; }
  65%       { --rx: 3deg; --ry: -5deg; }
  85%, 100% { --rx: 0deg; --ry: 0deg; }
}
@keyframes spot-loop {
  0%, 15%   { --sp: 0; --mx: 15%; --my: 20%; }
  30%       { --sp: 1; }
  50%       { --mx: 85%; --my: 30%; }
  70%       { --mx: 50%; --my: 80%; }
  85%, 100% { --sp: 0; }
}

@media (hover: none) {
  .card:active .card__bg { transform: scale(1.12); }
}
@media (prefers-reduced-motion: reduce) {
  .card__bg { transition: none; }
  .card.is-demo .card__bg { animation: none; }
  .card { transition: none; --rx: 0deg; --ry: 0deg; --sp: 0; }
  .card.is-demo { animation: none; }
}

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);
}

.stage {
  padding: clamp(6px, 2.4vw, 16px);
}

@property --mx {
  syntax: "<percentage>";
  inherits: true;
  initial-value: 50%;
}
@property --my {
  syntax: "<percentage>";
  inherits: true;
  initial-value: 50%;
}
@property --sp {
  syntax: "<number>";
  inherits: true;
  initial-value: 0;
}
@property --rx {
  syntax: "<angle>";
  inherits: true;
  initial-value: 0deg;
}
@property --ry {
  syntax: "<angle>";
  inherits: true;
  initial-value: 0deg;
}
.frame {
  perspective: 700px;
}

.card {
  position: relative;
  width: min(150px, 48vw);
  aspect-ratio: 4/3;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  outline: none;
  cursor: pointer;
  transform: rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg));
  transition: transform 600ms ease-out;
}

.card::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  pointer-events: none;
  background: radial-gradient(120px circle at var(--mx) var(--my), rgba(255, 255, 255, 0.32), transparent 70%);
  opacity: var(--sp);
}

.card__bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: linear-gradient(155deg, #2f6df6 0%, #fff7e6 100%);
  transform: scale(1);
  transition: transform 600ms ease-out;
}

.card__sun {
  position: absolute;
  top: 14%;
  right: 16%;
  width: 26%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: #ffd23f;
}

.card__hill {
  position: absolute;
  left: -10%;
  right: -10%;
  bottom: -12%;
  height: 46%;
  border-radius: 50% 50% 0 0/100% 100% 0 0;
  background: #17141a;
  opacity: 0.85;
}

.card__overlay {
  position: absolute;
  z-index: 1;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 8px 12px;
  background: linear-gradient(to top, rgba(23, 20, 26, 0.78), transparent);
}

.card__title {
  margin: 0 0 2px;
  font-weight: 700;
  font-size: clamp(12px, 3.4vw, 14px);
  line-height: 1.3;
  font-family: inherit;
  color: #ffffff;
}

.card__meta {
  margin: 0;
  font-weight: 500;
  font-size: clamp(11px, 3vw, 12px);
  line-height: 1.3;
  font-family: inherit;
  color: rgba(255, 255, 255, 0.8);
}

.card:hover .card__bg,
.card:focus-visible .card__bg,
.card:active .card__bg,
.card.is-demo .card__bg {
  transform: scale(1.12);
}

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

.card.is-demo {
  animation: tilt-loop 2s ease-out infinite, spot-loop 2s ease-out infinite;
}

@keyframes zoom-loop {
  0%, 20% {
    transform: scale(1);
  }
  50%, 75% {
    transform: scale(1.12);
  }
  100% {
    transform: scale(1);
  }
}
@keyframes tilt-loop {
  0%, 15% {
    --rx: 0deg;
    --ry: 0deg;
  }
  35% {
    --rx: -4deg;
    --ry: 5deg;
  }
  65% {
    --rx: 3deg;
    --ry: -5deg;
  }
  85%, 100% {
    --rx: 0deg;
    --ry: 0deg;
  }
}
@keyframes spot-loop {
  0%, 15% {
    --sp: 0;
    --mx: 15%;
    --my: 20%;
  }
  30% {
    --sp: 1;
  }
  50% {
    --mx: 85%;
    --my: 30%;
  }
  70% {
    --mx: 50%;
    --my: 80%;
  }
  85%, 100% {
    --sp: 0;
  }
}
@media (hover: none) {
  .card:active .card__bg {
    transform: scale(1.12);
  }
}
@media (prefers-reduced-motion: reduce) {
  .card__bg {
    transition: none;
  }
  .card.is-demo .card__bg {
    animation: none;
  }
  .card {
    transition: none;
    --rx: 0deg;
    --ry: 0deg;
    --sp: 0;
  }
  .card.is-demo {
    animation: none;
  }
}

// 커서 위치로 스포트라이트(--mx/--my/--sp) 와 미세 3D 틸트(--rx/--ry) 를 함께 만든다.
var card = document.querySelector('.card');
card.addEventListener('pointermove', function (e) {
  card.classList.remove('is-demo');
  var r = card.getBoundingClientRect();
  var px = (e.clientX - r.left) / r.width - .5;
  var py = (e.clientY - r.top) / r.height - .5;
  card.style.setProperty('--mx', ((e.clientX - r.left) / r.width * 100) + '%');
  card.style.setProperty('--my', ((e.clientY - r.top) / r.height * 100) + '%');
  card.style.setProperty('--sp', 1);
  card.style.setProperty('--rx', (-py * 8) + 'deg');
  card.style.setProperty('--ry', (px * 9) + 'deg');
});
card.addEventListener('pointerleave', function () {
  card.style.setProperty('--sp', 0);
  card.style.setProperty('--rx', '0deg');
  card.style.setProperty('--ry', '0deg');
});

import { useCallback, useRef } from "react";
import type { CSSProperties, PointerEvent, ReactNode } from "react";
import styles from "./BackgroundZoomCard.module.scss";

export type BackgroundZoomCardProps = {
  title: string;
  meta: string;
  /** 배경이 다 커지는 시간 (기본 600ms) */
  duration?: number;
  easing?: string;
  color?: string;
  media?: ReactNode;
};

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

export default function BackgroundZoomCard({
  title,
  meta,
  duration = 600,
  easing = "ease-out",
  color = "#fff7e6",
  media,
}: BackgroundZoomCardProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  const cardRef = useRef<HTMLElement>(null);

  // 커서 위치로 스포트라이트(--mx/--my/--sp) 와 미세 3D 틸트(--rx/--ry) 를 함께 만든다.
  const handlePointerMove = useCallback((e: PointerEvent<HTMLElement>) => {
    const card = cardRef.current;
    if (!card) return;
    const r = card.getBoundingClientRect();
    const px = (e.clientX - r.left) / r.width - 0.5;
    const py = (e.clientY - r.top) / r.height - 0.5;
    card.style.setProperty("--mx", `${((e.clientX - r.left) / r.width) * 100}%`);
    card.style.setProperty("--my", `${((e.clientY - r.top) / r.height) * 100}%`);
    card.style.setProperty("--sp", "1");
    card.style.setProperty("--rx", `${-py * 8}deg`);
    card.style.setProperty("--ry", `${px * 9}deg`);
  }, []);

  const handlePointerLeave = useCallback(() => {
    const card = cardRef.current;
    if (!card) return;
    card.style.setProperty("--sp", "0");
    card.style.setProperty("--rx", "0deg");
    card.style.setProperty("--ry", "0deg");
  }, []);

  return (
    <div className={styles.frame}>
      <article
        ref={cardRef}
        className={styles.card}
        style={vars}
        tabIndex={0}
        onPointerMove={handlePointerMove}
        onPointerLeave={handlePointerLeave}
      >
        <span className={styles.bg} aria-hidden="true">{media}</span>
        <div className={styles.overlay}>
          <h3 className={styles.title}>{title}</h3>
          <p className={styles.meta}>{meta}</p>
        </div>
      </article>
    </div>
  );
}