01불 켜지는 패드 누르기

<main class="stage">
<div class="rp is-demo" id="rp">
  <header class="rp__bar">
    <p class="rp__title">불 켜지는 패드 누르기</p>
    <button class="rp__restart" id="rpRestart" type="button" aria-label="다시 시작">
      <svg viewBox="0 0 256 256" aria-hidden="true" focusable="false"><g fill="currentColor"><path d="M216 128a88 88 0 1 1-88-88a88 88 0 0 1 88 88" opacity=".2"/><path d="M240 56v48a8 8 0 0 1-8 8h-48a8 8 0 0 1 0-16h27.4l-26.59-24.36l-.25-.24a80 80 0 1 0-1.67 114.78a8 8 0 0 1 11 11.63A95.44 95.44 0 0 1 128 224h-1.32a96 96 0 1 1 69.07-164L224 85.8V56a8 8 0 1 1 16 0"/></g></svg>
    </button>
  </header>
  <p class="rp__hint">켜진 패드만 눌립니다. 스페이스로도 누를 수 있어요</p>
  <div class="rp__board" id="rpBoard">
    <input class="rp__check" type="checkbox" id="rpP1" aria-label="1번 패드">
    <input class="rp__check" type="checkbox" id="rpP2" aria-label="2번 패드">
    <input class="rp__check" type="checkbox" id="rpP3" aria-label="3번 패드">
    <input class="rp__check" type="checkbox" id="rpP4" aria-label="4번 패드">
    <input class="rp__check" type="checkbox" id="rpP5" aria-label="5번 패드">
    <input class="rp__check" type="checkbox" id="rpP6" aria-label="6번 패드">
    <input class="rp__check" type="checkbox" id="rpP7" aria-label="7번 패드">
    <input class="rp__check" type="checkbox" id="rpP8" aria-label="8번 패드">
    <input class="rp__check" type="checkbox" id="rpP9" aria-label="9번 패드">
    <div class="rp__grid">
      <label class="rp__pad" for="rpP1" style="--i: 0"><span class="rp__no">1</span></label>
      <label class="rp__pad" for="rpP2" style="--i: 1"><span class="rp__no">2</span></label>
      <label class="rp__pad" for="rpP3" style="--i: 2"><span class="rp__no">3</span></label>
      <label class="rp__pad" for="rpP4" style="--i: 3"><span class="rp__no">4</span></label>
      <label class="rp__pad" for="rpP5" style="--i: 4"><span class="rp__no">5</span></label>
      <label class="rp__pad" for="rpP6" style="--i: 5"><span class="rp__no">6</span></label>
      <label class="rp__pad" for="rpP7" style="--i: 6"><span class="rp__no">7</span></label>
      <label class="rp__pad" for="rpP8" style="--i: 7"><span class="rp__no">8</span></label>
      <label class="rp__pad" for="rpP9" style="--i: 8"><span class="rp__no">9</span></label>
    </div>
    <p class="rp__done" role="status"><b>9개 패드 클리어!</b></p>
  </div>
  <p class="rp__tally"><span class="rp__tallyLabel">누른 수</span> <b class="rp__count"></b></p>
</div>
</main>

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

// 불 켜지는 패드 누르기 — 순수 CSS 게임. input[type=checkbox] 를 형제 결합자(~)로 연결해
// "바로 앞 패드가 :checked 일 때만 다음 패드에 불이 켜진다"는 연쇄를 만든다.
// 점수는 체크된 input 이 counter-increment 하고 아랫줄 .rp__count::after 가 content: counter() 로 읽는다.
// 9번째까지 체크됐다는 건 연쇄 위에서 1번부터 8번까지 전부 눌렸다는 뜻이므로, 완료 판정도 #rpP9:checked 하나로 충분하다.
// 격자 미리보기(.is-demo)는 9개 패드가 순서대로 눌리는 연출을 프리뷰 레이어(::before 리플 + ::after 채움)로 보여 준다.

$duration: $dur-loop;
$easing: $ease-spring;
$color: $subject-blue-deep;

@include stage($stage-ink);

.rp {
  display: flex; flex-direction: column; gap: $sp-2;
  width: 100%; max-width: 340px; height: 100%;
  counter-reset: rpTaps;
}

.rp__bar { display: flex; align-items: center; justify-content: space-between; gap: $sp-2; }
.rp__title { margin: 0; font-weight: 800; font-size: clamp(12px, 3vw, 15px); color: $subject-cream; }
.rp__restart {
  display: grid; place-items: center; width: clamp(24px, 5vw, 28px); aspect-ratio: 1; padding: 0;
  border: 2px solid rgba($subject-cream, .3); border-radius: $r-control;
  background: none; color: $subject-cream; cursor: pointer;
}
.rp__restart svg { width: 62%; height: 62%; }
.rp__restart:focus-visible { outline: 2px solid $subject-cream; outline-offset: 2px; }

.rp__hint { margin: 0; font-weight: 500; font-size: clamp(8px, 2.2vw, 10px); color: rgba($subject-cream, .72); }

.rp__board { position: relative; flex: 1 1 auto; min-height: 0; display: flex; }

// 체크박스는 화면에 그리지 않지만 카운터와 키보드 초점을 위해서 상자를 유지한다(display:none 은 카운터를 끊는다)
.rp__check { position: absolute; width: 1px; height: 1px; margin: -1px; opacity: 0; pointer-events: none; }
.rp__check:checked { counter-increment: rpTaps; }

.rp__grid { flex: 1 1 auto; display: grid; grid-template: repeat(3, 1fr) / repeat(3, 1fr); gap: $sp-2; }

.rp__pad {
  position: relative; display: grid; place-items: center;
  border-radius: $r-control; border: 2px solid rgba($subject-cream, .14);
  background-color: rgba($subject-cream, .05);
  pointer-events: none; cursor: default;
  transition: background-color $dur-quick $ease-out, border-color $dur-quick $ease-out,
              box-shadow $dur-quick $ease-out, transform $dur-quick $ease-pop;
}
.rp__no { position: relative; z-index: 1; font-weight: 800; font-size: clamp(11px, 3vw, 16px); color: rgba($subject-cream, .72); }
// 프리뷰 채움(::after)과 리플 고리(::before) — .is-demo 연출에서만 움직인다
.rp__pad::after { content: ""; position: absolute; inset: 0; z-index: 0; border-radius: inherit; background-color: $color; opacity: 0; }
.rp__pad::before { content: ""; position: absolute; inset: -2px; z-index: 2; border: 2px solid $subject-cream; border-radius: inherit; opacity: 0; }

// ── 연쇄 규칙 ───────────────────────────────────────────────
// 꺼진(아직 못 누른) 패드는 pointer-events:none 이라 클릭이 닿지 않고, 켜진 패드만 auto 로 살아난다
#rpP1:not(:checked) ~ .rp__grid .rp__pad:nth-child(1),
#rpP1:checked ~ .rp__grid .rp__pad:nth-child(2),
#rpP2:checked ~ .rp__grid .rp__pad:nth-child(3),
#rpP3:checked ~ .rp__grid .rp__pad:nth-child(4),
#rpP4:checked ~ .rp__grid .rp__pad:nth-child(5),
#rpP5:checked ~ .rp__grid .rp__pad:nth-child(6),
#rpP6:checked ~ .rp__grid .rp__pad:nth-child(7),
#rpP7:checked ~ .rp__grid .rp__pad:nth-child(8),
#rpP8:checked ~ .rp__grid .rp__pad:nth-child(9) {
  pointer-events: auto; cursor: pointer;
  background-color: $subject-cream; border-color: $subject-cream;
  box-shadow: 0 0 0 4px rgba($subject-cream, .16), 0 0 22px rgba($subject-cream, .3);
  .rp__no { color: $subject-ink; }
}

// 누른 패드는 색이 바뀌어 남는다 — 연쇄가 순서를 보장하므로 반칙 클릭은 애초에 불가능하다
#rpP1:checked ~ .rp__grid .rp__pad:nth-child(1),
#rpP2:checked ~ .rp__grid .rp__pad:nth-child(2),
#rpP3:checked ~ .rp__grid .rp__pad:nth-child(3),
#rpP4:checked ~ .rp__grid .rp__pad:nth-child(4),
#rpP5:checked ~ .rp__grid .rp__pad:nth-child(5),
#rpP6:checked ~ .rp__grid .rp__pad:nth-child(6),
#rpP7:checked ~ .rp__grid .rp__pad:nth-child(7),
#rpP8:checked ~ .rp__grid .rp__pad:nth-child(8),
#rpP9:checked ~ .rp__grid .rp__pad:nth-child(9) {
  background-color: $color; border-color: $color; box-shadow: none;
  .rp__no { color: $subject-cream; }
}

// 키보드 초점도 켜진 패드에만 보인다 — 초점 자체는 JS 가 켜진 패드로 옮긴다
#rpP1:focus-visible ~ .rp__grid .rp__pad:nth-child(1),
#rpP2:focus-visible ~ .rp__grid .rp__pad:nth-child(2),
#rpP3:focus-visible ~ .rp__grid .rp__pad:nth-child(3),
#rpP4:focus-visible ~ .rp__grid .rp__pad:nth-child(4),
#rpP5:focus-visible ~ .rp__grid .rp__pad:nth-child(5),
#rpP6:focus-visible ~ .rp__grid .rp__pad:nth-child(6),
#rpP7:focus-visible ~ .rp__grid .rp__pad:nth-child(7),
#rpP8:focus-visible ~ .rp__grid .rp__pad:nth-child(8),
#rpP9:focus-visible ~ .rp__grid .rp__pad:nth-child(9) {
  outline: 2px solid $subject-cream; outline-offset: 2px;
}

.rp__pad:active { transform: scale(.93); }

// 완료 — #rpP9 가 체크됐다면 1부터 8까지 전부 지나온 상태다
.rp__done { position: absolute; inset: 0; z-index: 3; display: none; place-items: center; margin: 0; }
#rpP9:checked ~ .rp__done { display: grid; }
.rp__done b {
  display: inline-block; padding: $sp-2 $sp-4; border-radius: $r-pill;
  background-color: $subject-cream; color: $subject-ink;
  font-weight: 800; font-size: clamp(11px, 2.8vw, 14px); box-shadow: $shadow-press;
  animation-name: rpDoneIn; animation-duration: $dur-enter; animation-timing-function: $easing;
  animation-iteration-count: 1; animation-fill-mode: both;
}
@keyframes rpDoneIn {
  from { opacity: 0; transform: scale(.8); }
  to   { opacity: 1; transform: scale(1); }
}

.rp__tally { display: flex; align-items: baseline; justify-content: space-between; gap: $sp-2; margin: 0; }
.rp__tallyLabel { font-weight: 700; font-size: clamp(9px, 2.4vw, 11px); color: rgba($subject-cream, .72); }
.rp__count { font-weight: 800; font-size: clamp(11px, 2.8vw, 14px); color: $subject-cream; }
.rp__count::after { content: counter(rpTaps) " / 9"; }

// ── 격자 미리보기 ───────────────────────────────────────────────
// 9개 패드가 2초 안에 순서대로 눌린다 — 눌림(scale)·채움(opacity)·리플 고리(scale+fade)를 같은 지연으로 묶는다
.rp.is-demo .rp__pad,
.rp.is-demo .rp__pad::after,
.rp.is-demo .rp__pad::before,
.rp.is-demo .rp__no {
  animation-duration: 380ms; animation-timing-function: $easing;
  animation-iteration-count: infinite; animation-fill-mode: backwards;
  animation-delay: calc(var(--i) * 180ms);
}
.rp.is-demo .rp__pad { animation-name: rpPress; }
.rp.is-demo .rp__pad::after { animation-name: rpFill; }
.rp.is-demo .rp__pad::before { animation-name: rpRipple; }
.rp.is-demo .rp__no { animation-name: rpNo; }
@keyframes rpPress {
  0%   { transform: scale(1); }
  28%  { transform: scale(.9); }
  58%  { transform: scale(1); }
  100% { transform: scale(1); }
}
@keyframes rpFill {
  0%   { opacity: 0; }
  26%  { opacity: 1; }
  78%  { opacity: 1; }
  100% { opacity: 0; }
}
@keyframes rpRipple {
  0%   { transform: scale(1); opacity: 0; }
  26%  { opacity: .9; transform: scale(1); }
  100% { transform: scale(1.32); opacity: 0; }
}
@keyframes rpNo {
  0%   { color: rgba($subject-cream, .72); }
  26%  { color: $subject-cream; }
  78%  { color: $subject-cream; }
  100% { color: rgba($subject-cream, .72); }
}

@media (max-width: 340px) {
  .rp { gap: $sp-1; }
  .rp__grid { gap: $sp-1; }
}

// reduce 에서는 연출을 끄고 현재 상태 한 장만 보여 준다 — 눌림 반응(transition)은 남긴다
@media (prefers-reduced-motion: reduce) {
  .rp.is-demo .rp__pad,
  .rp.is-demo .rp__pad::before,
  .rp.is-demo .rp__pad::after,
  .rp.is-demo .rp__no { animation: none !important; }
  .rp__done b { animation: none !important; }
  .rp__pad { transition: none !important; }
}

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);
}

.rp {
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
  max-width: 340px;
  height: 100%;
  counter-reset: rpTaps;
}

.rp__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.rp__title {
  margin: 0;
  font-weight: 800;
  font-size: clamp(12px, 3vw, 15px);
  color: #fff7e6;
}

.rp__restart {
  display: grid;
  place-items: center;
  width: clamp(24px, 5vw, 28px);
  aspect-ratio: 1;
  padding: 0;
  border: 2px solid rgba(255, 247, 230, 0.3);
  border-radius: 12px;
  background: none;
  color: #fff7e6;
  cursor: pointer;
}

.rp__restart svg {
  width: 62%;
  height: 62%;
}

.rp__restart:focus-visible {
  outline: 2px solid #fff7e6;
  outline-offset: 2px;
}

.rp__hint {
  margin: 0;
  font-weight: 500;
  font-size: clamp(8px, 2.2vw, 10px);
  color: rgba(255, 247, 230, 0.72);
}

.rp__board {
  position: relative;
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
}

.rp__check {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  opacity: 0;
  pointer-events: none;
}

.rp__check:checked {
  counter-increment: rpTaps;
}

.rp__grid {
  flex: 1 1 auto;
  display: grid;
  grid-template: repeat(3, 1fr)/repeat(3, 1fr);
  gap: 8px;
}

.rp__pad {
  position: relative;
  display: grid;
  place-items: center;
  border-radius: 12px;
  border: 2px solid rgba(255, 247, 230, 0.14);
  background-color: rgba(255, 247, 230, 0.05);
  pointer-events: none;
  cursor: default;
  transition: background-color 220ms ease-out, border-color 220ms ease-out, box-shadow 220ms ease-out, transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.rp__no {
  position: relative;
  z-index: 1;
  font-weight: 800;
  font-size: clamp(11px, 3vw, 16px);
  color: rgba(255, 247, 230, 0.72);
}

.rp__pad::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  border-radius: inherit;
  background-color: #0a4fe8;
  opacity: 0;
}

.rp__pad::before {
  content: "";
  position: absolute;
  inset: -2px;
  z-index: 2;
  border: 2px solid #fff7e6;
  border-radius: inherit;
  opacity: 0;
}

#rpP1:not(:checked) ~ .rp__grid .rp__pad:nth-child(1),
#rpP1:checked ~ .rp__grid .rp__pad:nth-child(2),
#rpP2:checked ~ .rp__grid .rp__pad:nth-child(3),
#rpP3:checked ~ .rp__grid .rp__pad:nth-child(4),
#rpP4:checked ~ .rp__grid .rp__pad:nth-child(5),
#rpP5:checked ~ .rp__grid .rp__pad:nth-child(6),
#rpP6:checked ~ .rp__grid .rp__pad:nth-child(7),
#rpP7:checked ~ .rp__grid .rp__pad:nth-child(8),
#rpP8:checked ~ .rp__grid .rp__pad:nth-child(9) {
  pointer-events: auto;
  cursor: pointer;
  background-color: #fff7e6;
  border-color: #fff7e6;
  box-shadow: 0 0 0 4px rgba(255, 247, 230, 0.16), 0 0 22px rgba(255, 247, 230, 0.3);
}
#rpP1:not(:checked) ~ .rp__grid .rp__pad:nth-child(1) .rp__no,
#rpP1:checked ~ .rp__grid .rp__pad:nth-child(2) .rp__no,
#rpP2:checked ~ .rp__grid .rp__pad:nth-child(3) .rp__no,
#rpP3:checked ~ .rp__grid .rp__pad:nth-child(4) .rp__no,
#rpP4:checked ~ .rp__grid .rp__pad:nth-child(5) .rp__no,
#rpP5:checked ~ .rp__grid .rp__pad:nth-child(6) .rp__no,
#rpP6:checked ~ .rp__grid .rp__pad:nth-child(7) .rp__no,
#rpP7:checked ~ .rp__grid .rp__pad:nth-child(8) .rp__no,
#rpP8:checked ~ .rp__grid .rp__pad:nth-child(9) .rp__no {
  color: #17141a;
}

#rpP1:checked ~ .rp__grid .rp__pad:nth-child(1),
#rpP2:checked ~ .rp__grid .rp__pad:nth-child(2),
#rpP3:checked ~ .rp__grid .rp__pad:nth-child(3),
#rpP4:checked ~ .rp__grid .rp__pad:nth-child(4),
#rpP5:checked ~ .rp__grid .rp__pad:nth-child(5),
#rpP6:checked ~ .rp__grid .rp__pad:nth-child(6),
#rpP7:checked ~ .rp__grid .rp__pad:nth-child(7),
#rpP8:checked ~ .rp__grid .rp__pad:nth-child(8),
#rpP9:checked ~ .rp__grid .rp__pad:nth-child(9) {
  background-color: #0a4fe8;
  border-color: #0a4fe8;
  box-shadow: none;
}
#rpP1:checked ~ .rp__grid .rp__pad:nth-child(1) .rp__no,
#rpP2:checked ~ .rp__grid .rp__pad:nth-child(2) .rp__no,
#rpP3:checked ~ .rp__grid .rp__pad:nth-child(3) .rp__no,
#rpP4:checked ~ .rp__grid .rp__pad:nth-child(4) .rp__no,
#rpP5:checked ~ .rp__grid .rp__pad:nth-child(5) .rp__no,
#rpP6:checked ~ .rp__grid .rp__pad:nth-child(6) .rp__no,
#rpP7:checked ~ .rp__grid .rp__pad:nth-child(7) .rp__no,
#rpP8:checked ~ .rp__grid .rp__pad:nth-child(8) .rp__no,
#rpP9:checked ~ .rp__grid .rp__pad:nth-child(9) .rp__no {
  color: #fff7e6;
}

#rpP1:focus-visible ~ .rp__grid .rp__pad:nth-child(1),
#rpP2:focus-visible ~ .rp__grid .rp__pad:nth-child(2),
#rpP3:focus-visible ~ .rp__grid .rp__pad:nth-child(3),
#rpP4:focus-visible ~ .rp__grid .rp__pad:nth-child(4),
#rpP5:focus-visible ~ .rp__grid .rp__pad:nth-child(5),
#rpP6:focus-visible ~ .rp__grid .rp__pad:nth-child(6),
#rpP7:focus-visible ~ .rp__grid .rp__pad:nth-child(7),
#rpP8:focus-visible ~ .rp__grid .rp__pad:nth-child(8),
#rpP9:focus-visible ~ .rp__grid .rp__pad:nth-child(9) {
  outline: 2px solid #fff7e6;
  outline-offset: 2px;
}

.rp__pad:active {
  transform: scale(0.93);
}

.rp__done {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: none;
  place-items: center;
  margin: 0;
}

#rpP9:checked ~ .rp__done {
  display: grid;
}

.rp__done b {
  display: inline-block;
  padding: 8px 16px;
  border-radius: 999px;
  background-color: #fff7e6;
  color: #17141a;
  font-weight: 800;
  font-size: clamp(11px, 2.8vw, 14px);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  animation-name: rpDoneIn;
  animation-duration: 600ms;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: 1;
  animation-fill-mode: both;
}

@keyframes rpDoneIn {
  from {
    opacity: 0;
    transform: scale(0.8);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}
.rp__tally {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  margin: 0;
}

.rp__tallyLabel {
  font-weight: 700;
  font-size: clamp(9px, 2.4vw, 11px);
  color: rgba(255, 247, 230, 0.72);
}

.rp__count {
  font-weight: 800;
  font-size: clamp(11px, 2.8vw, 14px);
  color: #fff7e6;
}

.rp__count::after {
  content: counter(rpTaps) " / 9";
}

.rp.is-demo .rp__pad,
.rp.is-demo .rp__pad::after,
.rp.is-demo .rp__pad::before,
.rp.is-demo .rp__no {
  animation-duration: 380ms;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: calc(var(--i) * 180ms);
}

.rp.is-demo .rp__pad {
  animation-name: rpPress;
}

.rp.is-demo .rp__pad::after {
  animation-name: rpFill;
}

.rp.is-demo .rp__pad::before {
  animation-name: rpRipple;
}

.rp.is-demo .rp__no {
  animation-name: rpNo;
}

@keyframes rpPress {
  0% {
    transform: scale(1);
  }
  28% {
    transform: scale(0.9);
  }
  58% {
    transform: scale(1);
  }
  100% {
    transform: scale(1);
  }
}
@keyframes rpFill {
  0% {
    opacity: 0;
  }
  26% {
    opacity: 1;
  }
  78% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}
@keyframes rpRipple {
  0% {
    transform: scale(1);
    opacity: 0;
  }
  26% {
    opacity: 0.9;
    transform: scale(1);
  }
  100% {
    transform: scale(1.32);
    opacity: 0;
  }
}
@keyframes rpNo {
  0% {
    color: rgba(255, 247, 230, 0.72);
  }
  26% {
    color: #fff7e6;
  }
  78% {
    color: #fff7e6;
  }
  100% {
    color: rgba(255, 247, 230, 0.72);
  }
}
@media (max-width: 340px) {
  .rp {
    gap: 4px;
  }
  .rp__grid {
    gap: 4px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .rp.is-demo .rp__pad,
  .rp.is-demo .rp__pad::before,
  .rp.is-demo .rp__pad::after,
  .rp.is-demo .rp__no {
    animation: none !important;
  }
  .rp__done b {
    animation: none !important;
  }
  .rp__pad {
    transition: none !important;
  }
}

// 게임 판정 자체는 전부 CSS(:checked 연쇄 + counter)다. JS 는 두 가지 보조만 한다 —
// 재시작(체크 해제)과 키보드 초점이 켜진 패드를 따라가는 일.
(function () {
  var root = document.getElementById('rp');
  var checks = [].slice.call(document.querySelectorAll('.rp__check'));
  var count = checks.length;
  function litIndex() {
    for (var i = 0; i < count; i++) { if (!checks[i].checked) { return i; } }
    return -1;
  }
  function sync(focusLit) {
    var k = litIndex();
    for (var i = 0; i < count; i++) { checks[i].tabIndex = (k === i || k < 0) ? 0 : -1; }
    if (focusLit && k >= 0) { checks[k].focus({ preventScroll: true }); }
  }
  root.addEventListener('change', function () {
    root.classList.remove('is-demo');
    sync(true);
  });
  document.getElementById('rpRestart').addEventListener('click', function () {
    for (var i = 0; i < count; i++) { checks[i].checked = false; }
    root.classList.remove('is-demo');
    sync(true);
  });
  sync(false);
})();

// LitReactionPad — vanilla 판(run/301/demo/01-lit-reaction-pad/index.html) 의 React 포트.
// 게임 판정은 전부 CSS(:checked 연쇄 + counter)다. React 는 상태(체크 9개)를 들고 있고
// 재시작과 키보드 초점(켜진 패드로 이동)만 담당한다.
import { useState } from "react";
import type { CSSProperties } from "react";
import styles from "./LitReactionPad.module.scss";

export type LitReactionPadProps = {
  duration?: number;
  easing?: string;
  accentColor?: string;
};

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

const TOTAL = 9;
const TITLE = "불 켜지는 패드 누르기";
const HINT = "켜진 패드만 눌립니다. 스페이스로도 누를 수 있어요";
const RESTART_LABEL = "다시 시작";
const PAD_LABEL = "{n}번 패드";
const DONE_TEXT = "9개 패드 클리어!";
const TALLY_LABEL = "누른 수";

function RestartIcon() {
  return (
    <svg viewBox="0 0 256 256" aria-hidden="true" focusable="false">
      <g fill="currentColor">
        <path d="M216 128a88 88 0 1 1-88-88a88 88 0 0 1 88 88" opacity=".2" />
        <path d="M240 56v48a8 8 0 0 1-8 8h-48a8 8 0 0 1 0-16h27.4l-26.59-24.36l-.25-.24a80 80 0 1 0-1.67 114.78a8 8 0 0 1 11 11.63A95.44 95.44 0 0 1 128 224h-1.32a96 96 0 1 1 69.07-164L224 85.8V56a8 8 0 1 1 16 0" />
      </g>
    </svg>
  );
}

export default function LitReactionPad({
  duration = 2000,
  easing = "cubic-bezier(.2, .8, .2, 1)",
  accentColor = "#0a4fe8",
}: LitReactionPadProps) {
  const [checks, setChecks] = useState<boolean[]>(Array(TOTAL).fill(false));
  const [demo, setDemo] = useState(true);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": accentColor };

  const litIndex = checks.findIndex((v) => !v);

  function toggle(i: number) {
    setDemo(false);
    setChecks((prev) => prev.map((v, k) => (k === i ? !v : v)));
  }
  function restart() {
    setDemo(false);
    setChecks(Array(TOTAL).fill(false));
  }
  function padVars(i: number): PadVars {
    return { "--i": String(i) };
  }
  function padLabel(i: number): string {
    return PAD_LABEL.replace("{n}", String(i + 1));
  }

  const cls = [styles.root, demo ? styles.isDemo : ""].filter(Boolean).join(" ");

  return (
    <main className={styles.stage}>
      <div className={cls} style={vars}>
        <header className={styles.bar}>
          <p className={styles.title}>{TITLE}</p>
          <button className={styles.restart} type="button" aria-label={RESTART_LABEL} onClick={restart}>
            <RestartIcon />
          </button>
        </header>
        <p className={styles.hint}>{HINT}</p>
        <div className={styles.board}>
          {checks.map((v, i) => (
            <input
              key={i}
              className={styles.check}
              type="checkbox"
              id={`rpP${i + 1}`}
              aria-label={padLabel(i)}
              checked={v}
              tabIndex={litIndex === i || litIndex < 0 ? 0 : -1}
              onChange={() => toggle(i)}
            />
          ))}
          <div className={styles.grid}>
            {checks.map((v, i) => (
              <label key={i} className={styles.pad} htmlFor={`rpP${i + 1}`} style={padVars(i)}>
                <span className={styles.no}>{i + 1}</span>
              </label>
            ))}
          </div>
          <p className={styles.done} role="status">
            <b>{DONE_TEXT}</b>
          </p>
        </div>
        <p className={styles.tally}>
          <span className={styles.tallyLabel}>{TALLY_LABEL}</span> <b className={styles.count}></b>
        </p>
      </div>
    </main>
  );
}