03Spotlight card reveal

<main class="stage">
  <div class="sp-card is-demo">
    <span class="sp-card__spot" aria-hidden="true"></span>
    <p class="sp-card__text">Hover over it and<br>the hidden text<br>catches the light and appears</p>
  </div>
</main>

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

$duration: $dur-quick;
$easing: $ease-out;
$color: $stage-paper;

@include stage($stage-ink);

.sp-card {
  position: relative;
  width: min(240px, 78vw);
  height: 150px;
  overflow: hidden;
  border-radius: $r-card;
  background: #201c26;
  border: 1px solid rgba(255, 255, 255, .08);
  display: grid;
  place-items: center;
}

.sp-card__spot {
  position: absolute;
  left: -90px;
  top: -90px;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 255, 255, .9) 0%, rgba(47, 109, 246, .5) 45%, transparent 72%);
  mix-blend-mode: soft-light;
  transform: translate(120px, 75px);
  transition: transform $duration $easing;
  pointer-events: none;
}

.sp-card__text {
  position: relative;
  z-index: 1;
  margin: 0;
  padding: $sp-4;
  text-align: center;
  font-size: 14px;
  line-height: 1.5;
  font-weight: 700;
  color: rgba(255, 255, 255, .72);   // .22 + screen 은 스포트라이트 밖에서 1.95:1 이었다 — AA 4.5
  mix-blend-mode: screen;
}

@media (hover: none), (pointer: coarse) {
  .sp-card__spot { opacity: 0; }                        // 터치엔 계속 따라다닐 커서가 없다 — 꺼서 항상 어두운 카드로 둔다
  .sp-card__text { color: rgba(255, 255, 255, .85); }    // 대신 글자 자체를 밝혀 내용은 읽히게 한다
}

// 데모 강제 루프 — 스포트라이트가 카드 위를 대각선으로 오간다
.sp-card.is-demo .sp-card__spot { animation: sp-sweep $dur-loop $easing infinite; transition: none; }
@keyframes sp-sweep {
  0%, 6%    { transform: translate(10px, 10px); }
  50%       { transform: translate(190px, 130px); }
  94%, 100% { transform: translate(10px, 10px); }
}

@media (prefers-reduced-motion: reduce) {
  .sp-card__spot { animation: none !important; transition: none !important; transform: translate(120px, 75px); }
  .sp-card__text { color: rgba(255, 255, 255, .72); }
}

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);
}

.sp-card {
  position: relative;
  width: min(240px, 78vw);
  height: 150px;
  overflow: hidden;
  border-radius: 16px;
  background: #201c26;
  border: 1px solid rgba(255, 255, 255, 0.08);
  display: grid;
  place-items: center;
}

.sp-card__spot {
  position: absolute;
  left: -90px;
  top: -90px;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.9) 0%, rgba(47, 109, 246, 0.5) 45%, transparent 72%);
  mix-blend-mode: soft-light;
  transform: translate(120px, 75px);
  transition: transform 220ms ease-out;
  pointer-events: none;
}

.sp-card__text {
  position: relative;
  z-index: 1;
  margin: 0;
  padding: 16px;
  text-align: center;
  font-size: 14px;
  line-height: 1.5;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.72);
  mix-blend-mode: screen;
}

@media (hover: none), (pointer: coarse) {
  .sp-card__spot {
    opacity: 0;
  }
  .sp-card__text {
    color: rgba(255, 255, 255, 0.85);
  }
}
.sp-card.is-demo .sp-card__spot {
  animation: sp-sweep 2s ease-out infinite;
  transition: none;
}

@keyframes sp-sweep {
  0%, 6% {
    transform: translate(10px, 10px);
  }
  50% {
    transform: translate(190px, 130px);
  }
  94%, 100% {
    transform: translate(10px, 10px);
  }
}
@media (prefers-reduced-motion: reduce) {
  .sp-card__spot {
    animation: none !important;
    transition: none !important;
    transform: translate(120px, 75px);
  }
  .sp-card__text {
    color: rgba(255, 255, 255, 0.72);
  }
}

(function () {
  var card = document.querySelector('.sp-card');
  var spot = card.querySelector('.sp-card__spot');
  // 실제 사용자: pointermove 좌표를 그대로 스포트라이트 위치에 반영
  card.addEventListener('pointermove', function (e) {
    if (card.classList.contains('is-demo')) return;
    var r = card.getBoundingClientRect();
    spot.style.transform = 'translate(' + (e.clientX - r.left) + 'px,' + (e.clientY - r.top) + 'px)';
  });
  card.addEventListener('pointerenter', function () { card.classList.remove('is-demo'); card.classList.add('is-live'); });
  card.addEventListener('pointerleave', function () { card.classList.remove('is-live'); spot.style.transform = ''; });
})();

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

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

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

/** pointermove 좌표를 그대로 spotlight 엘리먼트의 translate 에 반영한다. mix-blend-mode 로 글자가 밝아진다 */
export default function CursorSpotlightCardReveal({
  text = "마우스를 올리면 숨어 있던 글자가 빛을 받아 드러난다",
  duration = 220,
  easing = "ease-out",
  color = "#ffffff",
}: CursorSpotlightCardRevealProps) {
  const spotRef = useRef<HTMLSpanElement>(null);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  const move = (e: PointerEvent<HTMLDivElement>) => {
    const spot = spotRef.current;
    if (!spot) return;
    const r = e.currentTarget.getBoundingClientRect();
    spot.style.transform = `translate(${e.clientX - r.left}px,${e.clientY - r.top}px)`;
  };
  const leave = () => { if (spotRef.current) spotRef.current.style.transform = ""; };

  return (
    <div className={styles.card} style={vars} onPointerMove={move} onPointerLeave={leave}>
      <span ref={spotRef} className={styles.spot} aria-hidden="true" />
      <p className={styles.text}>{text}</p>
    </div>
  );
}