09Lightbox That Instantly Reflects Reduced Motion

<main class="stage">
<div class="scene is-demo" id="scene">
  <div class="switchRow">
    <button class="switch" id="switchBtn" type="button" role="switch" aria-checked="false" aria-label="Reduced-motion simulation">
      <span class="switchKnob" id="switchKnob"></span>
    </button>
    <p class="switchLabel" id="switchLabel">Motion normal</p>
  </div>
  <ul class="grid" id="grid">
    <li><button class="thumb" id="thumb0" type="button" aria-haspopup="dialog"><span class="thumbImg"></span></button></li>
  </ul>
  <div class="backdrop" id="backdrop"></div>
  <div class="lightbox" id="lightbox" role="dialog" aria-modal="true" aria-hidden="true" aria-label="Reduced motion comparison">
    <span class="fullImg" id="fullImg"></span>
    <p class="modeNote" id="modeNote">Opened with normal motion</p>
    <button class="closeBtn" id="closeBtn" type="button">Close</button>
  </div>
</div>
</main>

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

// 변수 3개
$duration: $dur-base;
$easing: $ease-out;
$color: $subject-lilac;

// 계산 겹: index.html 은 실제 `matchMedia('(prefers-reduced-motion: reduce)')` 결과와 화면의
// 시뮬레이션 스위치를 OR 로 합친 effectiveReduce() 하나로 열기/닫기 트윈 실행 여부를 결정한다 —
// 실제 설정이 바뀌는 change 이벤트와 스위치 클릭 둘 다 같은 함수로 수렴한다.
@include stage($stage-ink);

.scene {
  position: relative;
  width: 320px;
  height: 180px;
  border-radius: $r-card;
  overflow: hidden;
  box-shadow: $shadow-raised;
  background: linear-gradient(160deg, #232a3a, $stage-ink 85%);
}

.switchRow {
  position: absolute;
  top: $sp-2;
  left: $sp-2;
  display: flex;
  align-items: center;
  gap: $sp-2;
  z-index: 2;
}

.switch {
  appearance: none;
  border: none;
  width: 36px;
  height: 20px;
  border-radius: $r-pill;
  background: rgba($subject-cream, .28);
  padding: $sp-1;
  cursor: pointer;
  position: relative;

  &.is-on { background: $color; }
}

.switchKnob {
  display: block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: $subject-cream;
  transform: translateX(0);
  transition: transform $dur-quick $ease-out;

  .switch.is-on & { transform: translateX(16px); }
}

.switchLabel {
  margin: 0;
  font-size: 9px;
  font-weight: 700;
  color: $subject-cream;
}

.grid {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

.thumb {
  appearance: none;
  border: none;
  background: none;
  padding: 0;
  cursor: pointer;

  &:focus-visible .thumbImg { outline: 2px solid $color; outline-offset: 2px; }
}

.thumbImg {
  display: block;
  width: 72px;
  height: 72px;
  border-radius: $r-sm;
  box-shadow: $shadow-press;
  background: linear-gradient(135deg, $subject-lilac, $subject-blue);
}

.backdrop {
  position: absolute;
  inset: 0;
  background: $subject-ink;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.lightbox {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: $sp-2;
  visibility: hidden;
}

.fullImg {
  display: block;
  width: 190px;
  height: 110px;
  border-radius: $r-card;
  background: linear-gradient(135deg, $subject-lilac, $subject-blue 55%, $subject-sky);
}

.modeNote {
  margin: 0;
  font-size: 10px;
  font-weight: 700;
  color: $subject-cream;
  background: rgba(#000, .38);
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
}

.closeBtn {
  position: absolute;
  top: $sp-2;
  right: $sp-2;
  appearance: none;
  border: none;
  border-radius: $r-pill;
  padding: $sp-1 $sp-3;
  font-size: 11px;
  font-weight: 600;
  color: $subject-ink;
  background: rgba($subject-cream, .92);
  cursor: pointer;

  &:focus-visible { outline: 2px solid $color; outline-offset: 2px; }
}

@media (max-width: 340px) {
  .scene { width: 220px; height: 124px; }
  .fullImg { width: 140px; height: 84px; }
  .switchLabel { font-size: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  // 실사용 경로 적용 — 열기/닫기 트윈은 index.html 의 effectiveReduce() 가 실제 매체쿼리를 읽어
  // reduce 시 animate() 를 건너뛰고 즉시 최종 상태로 처리한다. 스위치 노브의 슬라이드도 여기서 끈다.
  .switchKnob { transition: none; }
  .closeBtn, .thumb { transition: 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);
}

.scene {
  position: relative;
  width: 320px;
  height: 180px;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  background: linear-gradient(160deg, #232a3a, #17141a 85%);
}

.switchRow {
  position: absolute;
  top: 8px;
  left: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
  z-index: 2;
}

.switch {
  appearance: none;
  border: none;
  width: 36px;
  height: 20px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.28);
  padding: 4px;
  cursor: pointer;
  position: relative;
}
.switch.is-on {
  background: #b9a0ff;
}

.switchKnob {
  display: block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #fff7e6;
  transform: translateX(0);
  transition: transform 220ms ease-out;
}
.switch.is-on .switchKnob {
  transform: translateX(16px);
}

.switchLabel {
  margin: 0;
  font-size: 9px;
  font-weight: 700;
  color: #fff7e6;
}

.grid {
  position: absolute;
  inset: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: center;
}

.thumb {
  appearance: none;
  border: none;
  background: none;
  padding: 0;
  cursor: pointer;
}
.thumb:focus-visible .thumbImg {
  outline: 2px solid #b9a0ff;
  outline-offset: 2px;
}

.thumbImg {
  display: block;
  width: 72px;
  height: 72px;
  border-radius: 8px;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  background: linear-gradient(135deg, #b9a0ff, #2f6df6);
}

.backdrop {
  position: absolute;
  inset: 0;
  background: #17141a;
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.lightbox {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  visibility: hidden;
}

.fullImg {
  display: block;
  width: 190px;
  height: 110px;
  border-radius: 16px;
  background: linear-gradient(135deg, #b9a0ff, #2f6df6 55%, #6ec8ff);
}

.modeNote {
  margin: 0;
  font-size: 10px;
  font-weight: 700;
  color: #fff7e6;
  background: rgba(0, 0, 0, 0.38);
  padding: 4px 12px;
  border-radius: 999px;
}

.closeBtn {
  position: absolute;
  top: 8px;
  right: 8px;
  appearance: none;
  border: none;
  border-radius: 999px;
  padding: 4px 12px;
  font-size: 11px;
  font-weight: 600;
  color: #17141a;
  background: rgba(255, 247, 230, 0.92);
  cursor: pointer;
}
.closeBtn:focus-visible {
  outline: 2px solid #b9a0ff;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .scene {
    width: 220px;
    height: 124px;
  }
  .fullImg {
    width: 140px;
    height: 84px;
  }
  .switchLabel {
    font-size: 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .switchKnob {
    transition: none;
  }
  .closeBtn, .thumb {
    transition: none;
  }
}

(function () {
  var OPEN_MS = 420;
  var CLOSE_MS = 320;
  var HOLD_MS = 380;
  var LOOP_MS = 2000;

  var scene = document.getElementById('scene');
  var backdrop = document.getElementById('backdrop');
  var lightbox = document.getElementById('lightbox');
  var fullImg = document.getElementById('fullImg');
  var modeNote = document.getElementById('modeNote');
  var closeBtn = document.getElementById('closeBtn');
  var thumb = document.getElementById('thumb0');
  var switchBtn = document.getElementById('switchBtn');
  var switchLabel = document.getElementById('switchLabel');

  // 실제 OS/브라우저 설정 — 이 값이 true 면 시뮬레이션 스위치와 무관하게 항상 즉시 전환한다
  var mql = window.matchMedia('(prefers-reduced-motion: reduce)');
  var realReduce = mql.matches;
  // 시연용 시뮬레이션 스위치 — 실제 설정이 "보통"이어도 이 편의 라이트박스만 강제로 즉시 전환해 차이를 비교한다
  var simulateReduce = false;

  function effectiveReduce() { return realReduce || simulateReduce; }

  var open = false;
  var timers = [];

  function clamp(v, lo, hi) { return Math.min(hi, Math.max(lo, v)); }
  function easeOutCubic(t) { return 1 - Math.pow(1 - t, 3); }

  function animate(duration, onFrame, onDone) {
    if (effectiveReduce()) { onFrame(1); if (onDone) onDone(); return; }
    var start = performance.now();
    function frame(now) {
      var p = clamp((now - start) / duration, 0, 1);
      onFrame(easeOutCubic(p));
      if (p < 1) requestAnimationFrame(frame);
      else if (onDone) onDone();
    }
    requestAnimationFrame(frame);
  }

  function updateSwitchUI() {
    switchBtn.setAttribute('aria-checked', simulateReduce ? 'true' : 'false');
    switchBtn.classList.toggle('is-on', simulateReduce);
    if (realReduce) {
      switchLabel.textContent = 'Actual setting: reduced motion on';
    } else {
      switchLabel.textContent = simulateReduce ? 'Reduced-motion simulation on' : 'Motion normal';
    }
  }

  function setSimulate(on) {
    simulateReduce = on;
    updateSwitchUI();
  }

  function openFrom() {
    if (open) return;
    open = true;
    var reduceNow = effectiveReduce();
    modeNote.textContent = reduceNow ? 'Switched instantly (reduced motion)' : 'Opened with normal motion';
    fullImg.style.transform = 'scale(.82)';
    fullImg.style.opacity = '0';
    lightbox.style.visibility = 'visible';
    lightbox.setAttribute('aria-hidden', 'false');
    backdrop.style.visibility = 'visible';
    animate(OPEN_MS, function (e) {
      fullImg.style.transform = 'scale(' + (0.82 + 0.18 * e).toFixed(4) + ')';
      fullImg.style.opacity = e.toFixed(3);
      backdrop.style.opacity = (0.74 * e).toFixed(3);
    }, function () {
      closeBtn.focus({ preventScroll: true });
    });
  }

  function closeLightbox() {
    if (!open) return;
    animate(CLOSE_MS, function (e) {
      fullImg.style.opacity = (1 - e).toFixed(3);
      backdrop.style.opacity = (0.74 * (1 - e)).toFixed(3);
    }, function () {
      lightbox.style.visibility = 'hidden';
      lightbox.setAttribute('aria-hidden', 'true');
      backdrop.style.visibility = 'hidden';
      open = false;
      thumb.focus({ preventScroll: true });
    });
  }

  function human() {
    if (scene.classList.contains('is-demo')) {
      scene.classList.remove('is-demo');
      timers.forEach(function (id) { clearTimeout(id); clearInterval(id); });
      timers = [];
    }
  }

  thumb.addEventListener('click', function () { human(); openFrom(); });
  closeBtn.addEventListener('click', function () { human(); closeLightbox(); });
  backdrop.addEventListener('click', function () { human(); closeLightbox(); });
  switchBtn.addEventListener('click', function () { human(); setSimulate(!simulateReduce); });
  document.addEventListener('keydown', function (e) {
    if (open && e.key === 'Escape') { human(); closeLightbox(); }
  });

  // 실제 설정이 바뀌면(운영체제·브라우저 쪽) 즉시 반영한다 — 시뮬레이션과 별개의 진짜 경로
  function onRealChange(e) {
    realReduce = e.matches;
    updateSwitchUI();
  }
  if (mql.addEventListener) mql.addEventListener('change', onRealChange);
  else if (mql.addListener) mql.addListener(onRealChange);

  function cycle() {
    setSimulate(false);
    openFrom();
    timers.push(setTimeout(closeLightbox, OPEN_MS + HOLD_MS));
    timers.push(setTimeout(function () {
      setSimulate(true);
      openFrom();
    }, OPEN_MS + HOLD_MS + CLOSE_MS + 160));
    timers.push(setTimeout(closeLightbox, OPEN_MS + HOLD_MS + CLOSE_MS + 160 + HOLD_MS));
  }

  updateSwitchUI();
  if (!realReduce) {
    cycle();
    timers.push(setInterval(function () {
      if (scene.classList.contains('is-demo')) cycle();
    }, LOOP_MS));
  } else {
    // 실제 설정이 이미 줄이기라면 루프를 돌리지 않고 정적 상태로 둔다 — 실사용 경로 그대로
    modeNote.textContent = 'Switched instantly (reduced motion)';
  }
})();

import { useEffect, useRef } from 'react';
import styles from './ReducedMotionInstant.module.scss';

const OPEN_MS = 420;
const CLOSE_MS = 320;
const HOLD_MS = 380;
const LOOP_MS = 2000;

export default function ReducedMotionInstant() {
  const sceneRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const scene0 = sceneRef.current;
    if (!scene0) return undefined;
    const backdrop0 = scene0.querySelector<HTMLDivElement>('.' + styles.backdrop);
    const lightbox0 = scene0.querySelector<HTMLDivElement>('.' + styles.lightbox);
    const fullImg0 = scene0.querySelector<HTMLSpanElement>('.' + styles.fullImg);
    const modeNote0 = scene0.querySelector<HTMLParagraphElement>('.' + styles.modeNote);
    const closeBtn0 = scene0.querySelector<HTMLButtonElement>('.' + styles.closeBtn);
    const thumb0 = scene0.querySelector<HTMLButtonElement>('.' + styles.thumb);
    const switchBtn0 = scene0.querySelector<HTMLButtonElement>('.' + styles.switch);
    const switchLabel0 = scene0.querySelector<HTMLParagraphElement>('.' + styles.switchLabel);
    if (!backdrop0 || !lightbox0 || !fullImg0 || !modeNote0 || !closeBtn0 || !thumb0 || !switchBtn0 || !switchLabel0) return undefined;
    const scene = scene0;
    const backdrop = backdrop0;
    const lightbox = lightbox0;
    const fullImg = fullImg0;
    const modeNote = modeNote0;
    const closeBtn = closeBtn0;
    const thumb = thumb0;
    const switchBtn = switchBtn0;
    const switchLabel = switchLabel0;

    // 실제 OS/브라우저 설정 — 이 값이 true 면 시뮬레이션 스위치와 무관하게 항상 즉시 전환한다
    const mql = window.matchMedia('(prefers-reduced-motion: reduce)');
    let realReduce = mql.matches;
    // 시연용 시뮬레이션 스위치 — 실제 설정이 "보통"이어도 이 편의 라이트박스만 강제로 즉시 전환해 차이를 비교한다
    let simulateReduce = false;

    function effectiveReduce() { return realReduce || simulateReduce; }

    let open = false;
    let timers: number[] = [];

    function clamp(v: number, lo: number, hi: number) { return Math.min(hi, Math.max(lo, v)); }
    function easeOutCubic(t: number) { return 1 - Math.pow(1 - t, 3); }

    function animate(duration: number, onFrame: (e: number) => void, onDone?: () => void) {
      if (effectiveReduce()) { onFrame(1); if (onDone) onDone(); return; }
      const start = performance.now();
      function frame(now: number) {
        const p = clamp((now - start) / duration, 0, 1);
        onFrame(easeOutCubic(p));
        if (p < 1) requestAnimationFrame(frame);
        else if (onDone) onDone();
      }
      requestAnimationFrame(frame);
    }

    function updateSwitchUI() {
      switchBtn.setAttribute('aria-checked', simulateReduce ? 'true' : 'false');
      switchBtn.classList.toggle(styles['is-on'], simulateReduce);
      if (realReduce) {
        switchLabel.textContent = '실제 설정: 모션 줄이기 켜짐';
      } else {
        switchLabel.textContent = simulateReduce ? '모션 줄이기 시뮬레이션 켜짐' : '모션 보통';
      }
    }

    function setSimulate(on: boolean) {
      simulateReduce = on;
      updateSwitchUI();
    }

    function openFrom() {
      if (open) return;
      open = true;
      const reduceNow = effectiveReduce();
      modeNote.textContent = reduceNow ? '즉시 전환 (모션 줄이기)' : '보통 모션으로 열림';
      fullImg.style.transform = 'scale(.82)';
      fullImg.style.opacity = '0';
      lightbox.style.visibility = 'visible';
      lightbox.setAttribute('aria-hidden', 'false');
      backdrop.style.visibility = 'visible';
      animate(OPEN_MS, (e) => {
        fullImg.style.transform = 'scale(' + (0.82 + 0.18 * e).toFixed(4) + ')';
        fullImg.style.opacity = e.toFixed(3);
        backdrop.style.opacity = (0.74 * e).toFixed(3);
      }, () => {
        closeBtn.focus({ preventScroll: true });
      });
    }

    function closeLightbox() {
      if (!open) return;
      animate(CLOSE_MS, (e) => {
        fullImg.style.opacity = (1 - e).toFixed(3);
        backdrop.style.opacity = (0.74 * (1 - e)).toFixed(3);
      }, () => {
        lightbox.style.visibility = 'hidden';
        lightbox.setAttribute('aria-hidden', 'true');
        backdrop.style.visibility = 'hidden';
        open = false;
        thumb.focus({ preventScroll: true });
      });
    }

    function human() {
      if (scene.classList.contains(styles['is-demo'])) {
        scene.classList.remove(styles['is-demo']);
        timers.forEach((id) => { window.clearTimeout(id); window.clearInterval(id); });
        timers = [];
      }
    }

    function onThumbClick() { human(); openFrom(); }
    function onCloseClick() { human(); closeLightbox(); }
    function onBackdropClick() { human(); closeLightbox(); }
    function onSwitchClick() { human(); setSimulate(!simulateReduce); }
    function onKeydown(e: KeyboardEvent) {
      if (open && e.key === 'Escape') { human(); closeLightbox(); }
    }
    thumb.addEventListener('click', onThumbClick);
    closeBtn.addEventListener('click', onCloseClick);
    backdrop.addEventListener('click', onBackdropClick);
    switchBtn.addEventListener('click', onSwitchClick);
    document.addEventListener('keydown', onKeydown);

    // 실제 설정이 바뀌면(운영체제·브라우저 쪽) 즉시 반영한다 — 시뮬레이션과 별개의 진짜 경로
    function onRealChange(e: MediaQueryListEvent) {
      realReduce = e.matches;
      updateSwitchUI();
    }
    if (mql.addEventListener) mql.addEventListener('change', onRealChange);

    function cycle() {
      setSimulate(false);
      openFrom();
      timers.push(window.setTimeout(closeLightbox, OPEN_MS + HOLD_MS));
      timers.push(window.setTimeout(() => {
        setSimulate(true);
        openFrom();
      }, OPEN_MS + HOLD_MS + CLOSE_MS + 160));
      timers.push(window.setTimeout(closeLightbox, OPEN_MS + HOLD_MS + CLOSE_MS + 160 + HOLD_MS));
    }

    updateSwitchUI();
    if (!realReduce) {
      cycle();
      timers.push(window.setInterval(() => {
        if (scene.classList.contains(styles['is-demo'])) cycle();
      }, LOOP_MS));
    } else {
      // 실제 설정이 이미 줄이기라면 루프를 돌리지 않고 정적 상태로 둔다 — 실사용 경로 그대로
      modeNote.textContent = '즉시 전환 (모션 줄이기)';
    }

    return () => {
      timers.forEach((id) => { window.clearTimeout(id); window.clearInterval(id); });
      thumb.removeEventListener('click', onThumbClick);
      closeBtn.removeEventListener('click', onCloseClick);
      backdrop.removeEventListener('click', onBackdropClick);
      switchBtn.removeEventListener('click', onSwitchClick);
      document.removeEventListener('keydown', onKeydown);
      if (mql.removeEventListener) mql.removeEventListener('change', onRealChange);
    };
  }, []);

  return (
    <div className={`${styles.scene} ${styles['is-demo']}`} ref={sceneRef}>
      <div className={styles.switchRow}>
        <button className={styles.switch} type="button" role="switch" aria-checked="false" aria-label="모션 줄이기 시뮬레이션">
          <span className={styles.switchKnob} />
        </button>
        <p className={styles.switchLabel}>모션 보통</p>
      </div>
      <ul className={styles.grid}>
        <li><button className={styles.thumb} type="button" aria-haspopup="dialog"><span className={styles.thumbImg} /></button></li>
      </ul>
      <div className={styles.backdrop} />
      <div className={styles.lightbox} role="dialog" aria-modal="true" aria-hidden="true" aria-label="모션 줄이기 비교">
        <span className={styles.fullImg} />
        <p className={styles.modeNote}>보통 모션으로 열림</p>
        <button className={styles.closeBtn} type="button">닫기</button>
      </div>
    </div>
  );
}