06Energy gradient background

<svg width="0" height="0" style="position:absolute" aria-hidden="true">
  <defs>
    <symbol id="ico-waveform" viewBox="0 0 256 256" fill="currentColor"><path d="M208 96v64H48V96Z" opacity=".2"/><path d="M56 96v64a8 8 0 0 1-16 0V96a8 8 0 0 1 16 0m32-72a8 8 0 0 0-8 8v192a8 8 0 0 0 16 0V32a8 8 0 0 0-8-8m40 32a8 8 0 0 0-8 8v128a8 8 0 0 0 16 0V64a8 8 0 0 0-8-8m40 32a8 8 0 0 0-8 8v64a8 8 0 0 0 16 0V96a8 8 0 0 0-8-8m40-16a8 8 0 0 0-8 8v96a8 8 0 0 0 16 0V72a8 8 0 0 0-8-8"/></symbol>
    <symbol id="ico-play" viewBox="0 0 256 256" fill="currentColor"><path d="M228.23 134.69L84.15 222.81A8 8 0 0 1 72 216.12V39.88a8 8 0 0 1 12.15-6.69l144.08 88.12a7.82 7.82 0 0 1 0 13.38" opacity=".2"/><path d="M232.4 114.49L88.32 26.35a16 16 0 0 0-16.2-.3A15.86 15.86 0 0 0 64 39.87v176.26A15.94 15.94 0 0 0 80 232a16.07 16.07 0 0 0 8.36-2.35l144.04-88.14a15.88 15.88 0 0 0 0-27.02M80 215.94V40l143.83 88Z"/></symbol>
    <symbol id="ico-pause" viewBox="0 0 256 256" fill="currentColor"><path d="M208 48v160a8 8 0 0 1-8 8h-40a8 8 0 0 1-8-8V48a8 8 0 0 1 8-8h40a8 8 0 0 1 8 8M96 40H56a8 8 0 0 0-8 8v160a8 8 0 0 0 8 8h40a8 8 0 0 0 8-8V48a8 8 0 0 0-8-8" opacity=".2"/><path d="M200 32h-40a16 16 0 0 0-16 16v160a16 16 0 0 0 16 16h40a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m0 176h-40V48h40zM96 32H56a16 16 0 0 0-16 16v160a16 16 0 0 0 16 16h40a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m0 176H56V48h40z"/></symbol>
  </defs>
</svg>
<main class="stage">
<div class="ge is-demo" id="ge">
  <p class="ge__hint"><svg class="ge__ico" aria-hidden="true"><use href="#ico-waveform"/></svg><span>Press play and it moves with real sound</span></p>
  <div class="ge__panel">
    <p class="ge__label">Total energy</p>
    <div class="ge__meter" aria-hidden="true"><i class="ge__fill" id="fill"></i></div>
    <p class="ge__read">
      <span class="ge__readLabel">Level now</span>
      <b class="ge__readBox">
        <span class="ge__readText" id="energyText" aria-live="polite">32%</span>
        <span class="ge__loop" aria-hidden="true"><i>32%</i><i>74%</i><i>51%</i></span>
      </b>
    </p>
  </div>
  <div class="ge__foot">
    <button class="ge__play" id="play" type="button" aria-pressed="false">
      <svg class="ge__ico ge__ico--play" aria-hidden="true"><use href="#ico-play"/></svg>
      <svg class="ge__ico ge__ico--pause" aria-hidden="true"><use href="#ico-pause"/></svg>
      <span id="playLabel">Play</span>
    </button>
  </div>
</div>
</main>

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

// 에너지 그라디언트 배경 — 전체 에너지를 색상각 하나로 바꿔 무대를 물들인다.
// --hue 를 @property 로 <angle> 로 등록했기 때문에 키프레임에서 연속으로 보간된다.
// 등록 없이는 커스텀 속성이 문자열로 취급되어 그라디언트가 뚝뚝 끊겨 바뀐다 — 이 항목의 교육 포인트.

// 광과민성: 밝기(lightness)는 20%·13% 두 정지점에 고정하고 색상각만 210→340 도로 돌린다.
// 명도가 고정되면 큰 면적의 "밝기 반전"은 생기지 않는다 — 2초에 왕복 한 번(0.5Hz), WCAG 2.3.1 한계(초당 3회) 안.
$duration: $dur-base;
$easing: $ease-out;
$color: $stage-yellow;

@property --hue {
  syntax: '<angle>';
  inherits: false;
  initial-value: 210deg;
}

@include stage($stage-ink);

.ge {
  position: relative; display: flex; flex-direction: column; align-items: center; gap: $sp-4;
  width: 100%; max-width: 360px;
  padding: $sp-4; border-radius: $r-card;
  // 그라디언트는 --hue 를 쓰는 이 판 자신에 깔린다 — inherits: false 로 등록했으므로
  // 값을 쓰는 요소가 그 값을 직접 가져야 한다 (262 실측: 부모에 걸면 안 먹는다).
  background: linear-gradient(135deg, hsl(var(--hue) 72% 20%) 0%, hsl(calc(var(--hue) + 48deg) 62% 13%) 100%);
  transition: --hue $duration $ease-out;
}
.ge__hint {
  display: flex; align-items: center; gap: $sp-1; margin: 0;
  font-weight: 700; font-size: clamp(11px, 3vw, 12px); color: $subject-cream;
}
.ge__ico { width: 16px; height: 16px; color: $color; }

.ge__panel {
  display: flex; flex-direction: column; align-items: center; gap: $sp-2;
  width: 100%; padding: $sp-4; border-radius: $r-sm;
  background: rgba($subject-ink, .45);
}
.ge__label { margin: 0; font-weight: 800; font-size: clamp(12px, 3.2vw, 13px); color: $subject-cream; }
.ge__meter {
  width: 100%; height: 10px; border-radius: $r-pill; overflow: hidden;
  background: rgba($subject-cream, .16);
}
.ge__fill {
  display: block; height: 100%; width: 100%; border-radius: $r-pill;
  background: linear-gradient(90deg, $subject-mint 0%, $color 100%);
  transform-origin: left center;
  transform: scaleX(var(--e, .3));
  transition: transform $duration $ease-out;
}

.ge__read { margin: 0; display: flex; align-items: center; gap: $sp-2; }
.ge__readLabel { font-weight: 700; font-size: clamp(10px, 2.6vw, 11px); color: rgba($subject-cream, .82); }
.ge__readBox {
  position: relative; display: grid; place-items: center;
  min-width: 44px; height: 20px; border-radius: $r-xs; padding: 0 $sp-1;
  background: rgba($subject-cream, .16); color: $subject-cream;
  font-weight: 800; font-size: clamp(11px, 3vw, 12px); line-height: 1;
}
.ge__loop { position: absolute; inset: 0; display: grid; place-items: center; visibility: hidden; }
.ge__loop i { grid-area: 1 / 1; font-style: normal; visibility: hidden; }

.ge__foot { display: flex; align-items: center; justify-content: center; width: 100%; }
.ge__play {
  display: inline-flex; align-items: center; gap: $sp-1;
  border: 0; border-radius: $r-pill; padding: $sp-2 $sp-4;
  background: $color; color: $subject-ink; cursor: pointer;
  font-family: inherit; font-weight: 800; font-size: clamp(11px, 3vw, 12px); line-height: 1;
}
.ge__ico--pause { display: none; }
.ge__play[aria-pressed="true"] .ge__ico--play { display: none; }
.ge__play[aria-pressed="true"] .ge__ico--pause { display: inline-block; }
.ge__play .ge__ico { color: $subject-ink; }

// ── 격자 미리보기 루프 ─────────────────────────────────────────────
// 색상각이 210 → 340 → 210 으로 2초에 한 번 왕복(0.5Hz). 에너지 막대와 숫자가 같은 박자로 붙는다.
.ge.is-demo {
  animation-name: geHueLoop; animation-duration: $dur-loop; animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
  transition: none;
}
@keyframes geHueLoop {
  0%   { --hue: 210deg; }
  50%  { --hue: 340deg; }
  100% { --hue: 210deg; }
}
.ge.is-demo .ge__fill {
  animation-name: geFillLoop; animation-duration: $dur-loop; animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
  transition: none;
}
@keyframes geFillLoop {
  0%   { transform: scaleX(.32); }
  50%  { transform: scaleX(.78); }
  100% { transform: scaleX(.32); }
}
// 세기 숫자는 32 → 74 → 51 → 32 로 컷 교체. 지연 구간에 fill-mode 를 두지 않는다(작성 상태가 숨김).
.ge.is-demo .ge__readText { color: transparent; }
.ge.is-demo .ge__loop { visibility: visible; }
.ge.is-demo .ge__loop i {
  animation-name: geNumLoop; animation-duration: $dur-loop; animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}
.ge.is-demo .ge__loop i:nth-child(1) { animation-delay: 0ms; }
.ge.is-demo .ge__loop i:nth-child(2) { animation-delay: 666ms; }
.ge.is-demo .ge__loop i:nth-child(3) { animation-delay: 1332ms; }
@keyframes geNumLoop {
  0%, 33% { visibility: visible; }
  34%, 100% { visibility: hidden; }
}

@media (max-width: 340px) {
  .ge { gap: $sp-2; padding: $sp-3; }
  .ge__panel { padding: $sp-3; gap: $sp-1; }
  .ge__play { padding: $sp-1 $sp-3; }
}

// reduce 에서는 색이 도는 것도 멈춘다 — 초기값 색(210deg) 한 장으로 판이 서 있는다
@media (prefers-reduced-motion: reduce) {
  .ge.is-demo,
  .ge.is-demo .ge__fill,
  .ge.is-demo .ge__loop i { animation: none !important; }
  .ge.is-demo .ge__readText { color: $subject-cream !important; }
  .ge.is-demo .ge__loop { visibility: hidden !important; }
  .ge { transition: none !important; }
  .ge__fill { transition: none !important; }
}

@property --hue {
  syntax: "<angle>";
  inherits: false;
  initial-value: 210deg;
}
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);
}

.ge {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  width: 100%;
  max-width: 360px;
  padding: 16px;
  border-radius: 16px;
  background: linear-gradient(135deg, hsl(var(--hue), 72%, 20%) 0%, hsl(calc(var(--hue) + 48deg), 62%, 13%) 100%);
  transition: --hue 300ms ease-out;
}

.ge__hint {
  display: flex;
  align-items: center;
  gap: 4px;
  margin: 0;
  font-weight: 700;
  font-size: clamp(11px, 3vw, 12px);
  color: #fff7e6;
}

.ge__ico {
  width: 16px;
  height: 16px;
  color: #ffd23f;
}

.ge__panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 16px;
  border-radius: 8px;
  background: rgba(23, 20, 26, 0.45);
}

.ge__label {
  margin: 0;
  font-weight: 800;
  font-size: clamp(12px, 3.2vw, 13px);
  color: #fff7e6;
}

.ge__meter {
  width: 100%;
  height: 10px;
  border-radius: 999px;
  overflow: hidden;
  background: rgba(255, 247, 230, 0.16);
}

.ge__fill {
  display: block;
  height: 100%;
  width: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, #4cd4a6 0%, #ffd23f 100%);
  transform-origin: left center;
  transform: scaleX(var(--e, 0.3));
  transition: transform 300ms ease-out;
}

.ge__read {
  margin: 0;
  display: flex;
  align-items: center;
  gap: 8px;
}

.ge__readLabel {
  font-weight: 700;
  font-size: clamp(10px, 2.6vw, 11px);
  color: rgba(255, 247, 230, 0.82);
}

.ge__readBox {
  position: relative;
  display: grid;
  place-items: center;
  min-width: 44px;
  height: 20px;
  border-radius: 4px;
  padding: 0 4px;
  background: rgba(255, 247, 230, 0.16);
  color: #fff7e6;
  font-weight: 800;
  font-size: clamp(11px, 3vw, 12px);
  line-height: 1;
}

.ge__loop {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  visibility: hidden;
}

.ge__loop i {
  grid-area: 1/1;
  font-style: normal;
  visibility: hidden;
}

.ge__foot {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
}

.ge__play {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  border: 0;
  border-radius: 999px;
  padding: 8px 16px;
  background: #ffd23f;
  color: #17141a;
  cursor: pointer;
  font-family: inherit;
  font-weight: 800;
  font-size: clamp(11px, 3vw, 12px);
  line-height: 1;
}

.ge__ico--pause {
  display: none;
}

.ge__play[aria-pressed=true] .ge__ico--play {
  display: none;
}

.ge__play[aria-pressed=true] .ge__ico--pause {
  display: inline-block;
}

.ge__play .ge__ico {
  color: #17141a;
}

.ge.is-demo {
  animation-name: geHueLoop;
  animation-duration: 2s;
  animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
  transition: none;
}

@keyframes geHueLoop {
  0% {
    --hue: 210deg;
  }
  50% {
    --hue: 340deg;
  }
  100% {
    --hue: 210deg;
  }
}
.ge.is-demo .ge__fill {
  animation-name: geFillLoop;
  animation-duration: 2s;
  animation-timing-function: ease-in-out;
  animation-iteration-count: infinite;
  transition: none;
}

@keyframes geFillLoop {
  0% {
    transform: scaleX(0.32);
  }
  50% {
    transform: scaleX(0.78);
  }
  100% {
    transform: scaleX(0.32);
  }
}
.ge.is-demo .ge__readText {
  color: transparent;
}

.ge.is-demo .ge__loop {
  visibility: visible;
}

.ge.is-demo .ge__loop i {
  animation-name: geNumLoop;
  animation-duration: 2s;
  animation-timing-function: steps(1, end);
  animation-iteration-count: infinite;
}

.ge.is-demo .ge__loop i:nth-child(1) {
  animation-delay: 0ms;
}

.ge.is-demo .ge__loop i:nth-child(2) {
  animation-delay: 666ms;
}

.ge.is-demo .ge__loop i:nth-child(3) {
  animation-delay: 1332ms;
}

@keyframes geNumLoop {
  0%, 33% {
    visibility: visible;
  }
  34%, 100% {
    visibility: hidden;
  }
}
@media (max-width: 340px) {
  .ge {
    gap: 8px;
    padding: 12px;
  }
  .ge__panel {
    padding: 12px;
    gap: 4px;
  }
  .ge__play {
    padding: 4px 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ge.is-demo,
  .ge.is-demo .ge__fill,
  .ge.is-demo .ge__loop i {
    animation: none !important;
  }
  .ge.is-demo .ge__readText {
    color: #fff7e6 !important;
  }
  .ge.is-demo .ge__loop {
    visibility: hidden !important;
  }
  .ge {
    transition: none !important;
  }
  .ge__fill {
    transition: none !important;
  }
}

var root = document.getElementById('ge');
var fill = document.getElementById('fill');
var playBtn = document.getElementById('play');
var playLabel = document.getElementById('playLabel');
var energyText = document.getElementById('energyText');
var ctx = null, analyser = null, freq = null, timer = 0, playing = false;
function buildAudio() {
  ctx = new (window.AudioContext || window.webkitAudioContext)();
  analyser = ctx.createAnalyser();
  analyser.fftSize = 64;
  analyser.smoothingTimeConstant = 0.7;
  freq = new Uint8Array(analyser.frequencyBinCount);
  var out = ctx.createGain();
  out.gain.value = 0.06;
  out.connect(analyser);
  analyser.connect(ctx.destination);
  // 외부 음원 파일 없이 코드 진행을 직접 합성한다 — 네 박자마다 화음이 바뀐다.
  [196, 246.94, 293.66, 392].forEach(function (hz, n) {
    var osc = ctx.createOscillator();
    var amp = ctx.createGain();
    osc.type = n === 3 ? 'triangle' : 'sawtooth';
    osc.frequency.value = hz;
    amp.gain.value = 0;
    for (var beat = 0; beat < 64; beat++) {
      var at = ctx.currentTime + beat * 0.5;
      amp.gain.setValueAtTime(beat % 4 === n % 4 ? 0.9 : 0.25, at);
      amp.gain.exponentialRampToValueAtTime(0.02, at + 0.45);
    }
    osc.connect(amp); amp.connect(out); osc.start();
  });
}
function draw() {
  analyser.getByteFrequencyData(freq);
  var sum = 0;
  for (var k = 0; k < freq.length; k++) { sum += freq[k]; }
  var e = Math.min(1, (sum / (freq.length * 255)) * 2.6); // ×2.6 은 미터 눈금 보정 — 소리 자체는 바꾸지 않는다
  fill.style.setProperty('--e', e.toFixed(3));
  // --hue 는 이 그라디언트 판 자신의 등록된 속성이라 여기(그 판의 부모 .ge) 에 쓴다 —
  // inherits: false 로 등록했으니 값을 쓰는 요소가 스스로 가져야 한다 (262 실측).
  root.style.setProperty('--hue', (200 + e * 140).toFixed(1) + 'deg');
  var pct = Math.round(e * 100);
  if (energyText.textContent !== pct + '%') { energyText.textContent = pct + '%'; }
  timer = requestAnimationFrame(draw);
}
playBtn.addEventListener('click', function () {
  root.classList.remove('is-demo');
  if (!ctx) { buildAudio(); }
  playing = !playing;
  playBtn.setAttribute('aria-pressed', playing ? 'true' : 'false');
  playLabel.textContent = playing ? 'Stop' : 'Play';
  // 자동재생 정책: AudioContext 는 사용자 제스처 뒤 resume() 해야 소리가 난다.
  if (playing) { ctx.resume(); timer = requestAnimationFrame(draw); }
  else { ctx.suspend(); cancelAnimationFrame(timer); }
});

// GradientEnergy — vanilla 판(run/291/demo/06-audio-viz-gradient-energy/index.html) 의 React 포트.
// 전체 에너지를 색상각 하나로 바꿔 판을 물들인다. --hue 는 @property 로 등록돼 있어 연속 보간된다.
import { useEffect, useRef, useState } from "react";
import type { CSSProperties } from "react";
import styles from "./GradientEnergy.module.scss";

export type GradientEnergyProps = {
  /** 격자 미리보기용 2초 자동 루프. 재생을 누르면 꺼진다 */
  demo?: boolean;
  duration?: number;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
/** ambient 타입에 useRef<T> 의 null 합집합이 없어 로컬로 좁힌다 */
type Box<T> = { current: T };

export default function GradientEnergy({
  demo = true,
  duration = 300,
  easing = "ease-out",
  color = "#ffd23f",
}: GradientEnergyProps) {
  const [live, setLive] = useState(demo);
  const [playing, setPlaying] = useState(false);
  const [energy, setEnergy] = useState(0.32);
  const ctxBox = useRef(null) as Box<AudioContext | null>;
  const nodeBox = useRef(null) as Box<AnalyserNode | null>;
  const frameBox = useRef(0) as Box<number>;
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  useEffect(() => {
    return () => {
      cancelAnimationFrame(frameBox.current);
      if (ctxBox.current) {
        ctxBox.current.close();
      }
    };
  }, []);

  function buildAudio() {
    const ctx = new AudioContext();
    const analyser = ctx.createAnalyser();
    analyser.fftSize = 64;
    analyser.smoothingTimeConstant = 0.7;
    const out = ctx.createGain();
    out.gain.value = 0.06;
    out.connect(analyser);
    analyser.connect(ctx.destination);
    // 외부 음원 파일 없이 코드 진행을 직접 합성한다 — 네 박자마다 화음이 바뀐다.
    [196, 246.94, 293.66, 392].forEach((hz, n) => {
      const osc = ctx.createOscillator();
      const amp = ctx.createGain();
      osc.type = n === 3 ? "triangle" : "sawtooth";
      osc.frequency.value = hz;
      amp.gain.value = 0;
      for (let beat = 0; beat < 64; beat++) {
        const at = ctx.currentTime + beat * 0.5;
        amp.gain.setValueAtTime(beat % 4 === n % 4 ? 0.9 : 0.25, at);
        amp.gain.exponentialRampToValueAtTime(0.02, at + 0.45);
      }
      osc.connect(amp);
      amp.connect(out);
      osc.start();
    });
    ctxBox.current = ctx;
    nodeBox.current = analyser;
  }

  function draw() {
    const analyser = nodeBox.current;
    if (!analyser) {
      return;
    }
    const freq = new Uint8Array(analyser.frequencyBinCount);
    analyser.getByteFrequencyData(freq);
    let sum = 0;
    for (let k = 0; k < freq.length; k++) {
      sum += freq[k];
    }
    setEnergy(Math.min(1, (sum / (freq.length * 255)) * 2.6)); // ×2.6 은 미터 눈금 보정
    frameBox.current = requestAnimationFrame(draw);
  }

  function toggle() {
    setLive(false);
    if (!ctxBox.current) {
      buildAudio();
    }
    const ctx = ctxBox.current;
    if (!ctx) {
      return;
    }
    const next = !playing;
    setPlaying(next);
    // 자동재생 정책: AudioContext 는 사용자 제스처 뒤 resume() 해야 소리가 난다.
    if (next) {
      ctx.resume();
      frameBox.current = requestAnimationFrame(draw);
    } else {
      ctx.suspend();
      cancelAnimationFrame(frameBox.current);
    }
  }

  const cls = [styles.root, live ? styles.isDemo : ""].filter(Boolean).join(" ");
  // --hue 는 이 판 자신의 등록된 속성 — inherits: false 라 값을 쓰는 요소가 스스로 가져야 한다 (262 실측).
  const rootVars: Vars = { ...vars, "--hue": (200 + energy * 140).toFixed(1) + "deg" };
  return (
    <main className={styles.stage} style={rootVars}>
      <svg width="0" height="0" style={{ position: "absolute" }} aria-hidden="true">
        <defs>
          <symbol id="ico-waveform" viewBox="0 0 256 256" fill="currentColor">
            <path d="M208 96v64H48V96Z" opacity=".2" />
            <path d="M56 96v64a8 8 0 0 1-16 0V96a8 8 0 0 1 16 0m32-72a8 8 0 0 0-8 8v192a8 8 0 0 0 16 0V32a8 8 0 0 0-8-8m40 32a8 8 0 0 0-8 8v128a8 8 0 0 0 16 0V64a8 8 0 0 0-8-8m40 32a8 8 0 0 0-8 8v64a8 8 0 0 0 16 0V96a8 8 0 0 0-8-8m40-16a8 8 0 0 0-8 8v96a8 8 0 0 0 16 0V72a8 8 0 0 0-8-8" />
          </symbol>
          <symbol id="ico-play" viewBox="0 0 256 256" fill="currentColor">
            <path d="M228.23 134.69L84.15 222.81A8 8 0 0 1 72 216.12V39.88a8 8 0 0 1 12.15-6.69l144.08 88.12a7.82 7.82 0 0 1 0 13.38" opacity=".2" />
            <path d="M232.4 114.49L88.32 26.35a16 16 0 0 0-16.2-.3A15.86 15.86 0 0 0 64 39.87v176.26A15.94 15.94 0 0 0 80 232a16.07 16.07 0 0 0 8.36-2.35l144.04-88.14a15.88 15.88 0 0 0 0-27.02M80 215.94V40l143.83 88Z" />
          </symbol>
          <symbol id="ico-pause" viewBox="0 0 256 256" fill="currentColor">
            <path d="M208 48v160a8 8 0 0 1-8 8h-40a8 8 0 0 1-8-8V48a8 8 0 0 1 8-8h40a8 8 0 0 1 8 8M96 40H56a8 8 0 0 0-8 8v160a8 8 0 0 0 8 8h40a8 8 0 0 0 8-8V48a8 8 0 0 0-8-8" opacity=".2" />
            <path d="M200 32h-40a16 16 0 0 0-16 16v160a16 16 0 0 0 16 16h40a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m0 176h-40V48h40zM96 32H56a16 16 0 0 0-16 16v160a16 16 0 0 0 16 16h40a16 16 0 0 0 16-16V48a16 16 0 0 0-16-16m0 176H56V48h40z" />
          </symbol>
        </defs>
      </svg>
      <div className={cls}>
        <p className={styles.hint}>
          <svg className={styles.ico} aria-hidden="true">
            <use href="#ico-waveform" />
          </svg>
          <span>재생을 누르면 실제 소리로 움직입니다</span>
        </p>
        <div className={styles.panel}>
          <p className={styles.label}>전체 에너지</p>
          <div className={styles.meter} aria-hidden="true">
            <i className={styles.fill} style={{ transform: `scaleX(${energy.toFixed(3)})` }} />
          </div>
          <p className={styles.read}>
            <span className={styles.readLabel}>지금 세기</span>
            <b className={styles.readBox}>
              <span className={styles.readText} aria-live="polite">
                {Math.round(energy * 100)}%
              </span>
              <span className={styles.loop} aria-hidden="true">
                <i>32%</i>
                <i>74%</i>
                <i>51%</i>
              </span>
            </b>
          </p>
        </div>
        <div className={styles.foot}>
          <button className={styles.play} type="button" aria-pressed={playing} onClick={toggle}>
            <svg className={[styles.ico, playing ? styles.icoHidden : ""].join(" ")} aria-hidden="true">
              <use href="#ico-play" />
            </svg>
            <svg className={[styles.ico, playing ? "" : styles.icoHidden].join(" ")} aria-hidden="true">
              <use href="#ico-pause" />
            </svg>
            <span>{playing ? "정지" : "재생"}</span>
          </button>
        </div>
      </div>
    </main>
  );
}