01YouTube responsive embed — a video frame that recomputes its ratio from the available width

<main class="stage">
<section class="panel">
  <div class="frame" id="frame">
    <canvas class="thumb" id="thumb" width="320" height="180" aria-hidden="true"></canvas>
    <div class="playBtn" role="button" aria-label="Play">
      <svg class="playIcon" viewBox="0 0 24 24" aria-hidden="true"><polygon points="7,4 20,12 7,20"></polygon></svg>
    </div>
    <div class="scrim">
      <span class="scrimTitle">Embedded video preview</span>
      <span class="scrimChannel">Channel A</span>
    </div>
  </div>
  <div class="readout" id="readout">16:9 · 200 × 113px</div>
</section>
</main>

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

@include stage($stage-ink);

.panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
}

.frame {
  position: relative;
  width: 200px;
  aspect-ratio: 16 / 9;
  border-radius: $r-card;
  overflow: hidden;
  box-shadow: $shadow-raised;
}

.thumb {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.playBtn {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
}

.playIcon {
  width: 34px;
  height: 34px;
  filter: drop-shadow(0 2px 4px rgba(23, 20, 26, .4));

  polygon {
    fill: $subject-cream;
  }
}

.scrim {
  position: absolute;
  inset: auto 0 0 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: $sp-2;
  padding: $sp-2 $sp-3;
  background: rgba(23, 20, 26, .66);
}

.scrimTitle,
.scrimChannel {
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: $subject-cream;
  opacity: .96;
}

.scrimTitle {
  font-weight: 600;
  font-size: 11px;
  line-height: 1.3;
}

.scrimChannel {
  font-weight: 500;
  font-size: 10px;
  line-height: 1.3;
}

.readout {
  display: inline-flex;
  align-items: center;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: $subject-blue-deep;
  color: $subject-cream;
  font-family: "Space Mono", ui-monospace, monospace;
  font-weight: 700;
  font-size: 12px;
  line-height: 1.3;
}

@media (max-width: 340px) {
  .frame { width: 140px; }
  .playIcon { width: 24px; height: 24px; }
  .scrimTitle { font-size: 10px; }
  .scrimChannel { font-size: 9px; }
  .readout { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .frame { 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);
}

.panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.frame {
  position: relative;
  width: 200px;
  aspect-ratio: 16/9;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.thumb {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

.playBtn {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
}

.playIcon {
  width: 34px;
  height: 34px;
  filter: drop-shadow(0 2px 4px rgba(23, 20, 26, 0.4));
}
.playIcon polygon {
  fill: #fff7e6;
}

.scrim {
  position: absolute;
  inset: auto 0 0 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 8px 12px;
  background: rgba(23, 20, 26, 0.66);
}

.scrimTitle,
.scrimChannel {
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  color: #fff7e6;
  opacity: 0.96;
}

.scrimTitle {
  font-weight: 600;
  font-size: 11px;
  line-height: 1.3;
}

.scrimChannel {
  font-weight: 500;
  font-size: 10px;
  line-height: 1.3;
}

.readout {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border-radius: 999px;
  background: #0a4fe8;
  color: #fff7e6;
  font-family: "Space Mono", ui-monospace, monospace;
  font-weight: 700;
  font-size: 12px;
  line-height: 1.3;
}

@media (max-width: 340px) {
  .frame {
    width: 140px;
  }
  .playIcon {
    width: 24px;
    height: 24px;
  }
  .scrimTitle {
    font-size: 10px;
  }
  .scrimChannel {
    font-size: 9px;
  }
  .readout {
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .frame {
    transition: none;
  }
}

// 반응형 영상 프레임(01) — 폭을 sin 파형으로 바꾸면 aspect-ratio 가 세로를 다시 계산하고,
// 그 실측 높이를 매 프레임 getBoundingClientRect 로 읽어 리드아웃에 반영한다.
// 계산 겹: 폭 → 비율 재계산 → 실측 읽기 (transform·opacity 만 쓰는 원칙의 의도적 예외).
// 실키·실서버 요청 없음 — 폭 궤적은 고정 시나리오로 자동 재생한다.
(function () {
  function mulberry32(seed) {
    var a = seed >>> 0;
    return function () {
      a |= 0; a = (a + 0x6D2B79F5) | 0;
      var t = Math.imul(a ^ (a >>> 15), 1 | a);
      t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
      return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
    };
  }

  function drawSeedThumb(canvas, seed) {
    var ctx = canvas.getContext('2d');
    if (!ctx) return;
    var rnd = mulberry32(seed);
    var w = canvas.width, h = canvas.height;
    var hues = [216, 32, 268, 168];
    ctx.fillStyle = 'hsl(' + hues[Math.floor(rnd() * hues.length)] + ', 38%, 22%)';
    ctx.fillRect(0, 0, w, h);
    for (var i = 0; i < 6; i++) {
      var cx = rnd() * w, cy = rnd() * h, r = (0.18 + rnd() * 0.3) * Math.min(w, h);
      ctx.fillStyle = 'hsla(' + hues[Math.floor(rnd() * hues.length)] + ', ' + (44 + rnd() * 22).toFixed(1) + '%, ' + (38 + rnd() * 26).toFixed(1) + '%, .5)';
      ctx.beginPath(); ctx.arc(cx, cy, r, 0, Math.PI * 2); ctx.fill();
    }
    ctx.fillStyle = 'rgba(255, 247, 230, .06)';
    for (var j = 0; j < h; j += 4) ctx.fillRect(0, j, w, 1);
  }

  var frameEl = document.getElementById('frame');
  var thumbEl = document.getElementById('thumb');
  var readoutEl = document.getElementById('readout');
  if (!frameEl || !thumbEl || !readoutEl) return;

  drawSeedThumb(thumbEl, 101);

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var narrow = window.matchMedia('(max-width: 340px)').matches;
  var CYCLE_MS = 2000;
  var BASE = narrow ? 140 : 200;
  var RANGE = narrow ? 36 : 56;

  function apply(t) {
    var w = BASE + RANGE * Math.sin(2 * Math.PI * t / CYCLE_MS);
    frameEl.style.width = w.toFixed(1) + 'px';
    var rect = frameEl.getBoundingClientRect();
    readoutEl.textContent = '16:9 · ' + Math.round(w) + ' × ' + Math.round(rect.height) + 'px';
  }

  apply(0);

  if (reduce) return;

  var start = null;
  function loop(ts) {
    if (start === null) start = ts;
    var t = (ts - start) % CYCLE_MS;
    apply(t);
    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);
})();

import { useEffect, useRef } from "react";
import styles from "./EmbedYoutubeResponsive.module.scss";

// 반응형 영상 프레임 — 폭을 sin 파형으로 바꾸면 aspect-ratio 가 세로를 다시 계산하고,
// 그 실측 높이를 매 프레임 getBoundingClientRect 로 읽어 리드아웃에 반영한다.
// 계산 겹: 폭 → 비율 재계산 → 실측 읽기. 실키·실서버 요청 없음.
const CYCLE_MS = 2000;

function mulberry32(seed: number) {
  let a = seed >>> 0;
  return function () {
    a |= 0; a = (a + 0x6D2B79F5) | 0;
    let t = Math.imul(a ^ (a >>> 15), 1 | a);
    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
  };
}

function drawSeedThumb(canvas: HTMLCanvasElement, seed: number) {
  const ctx = canvas.getContext("2d");
  if (!ctx) return;
  const rnd = mulberry32(seed);
  const w = canvas.width, h = canvas.height;
  const hues = [216, 32, 268, 168];
  ctx.fillStyle = "hsl(" + hues[Math.floor(rnd() * hues.length)] + ", 38%, 22%)";
  ctx.fillRect(0, 0, w, h);
  for (let i = 0; i < 6; i++) {
    const cx = rnd() * w, cy = rnd() * h, r = (0.18 + rnd() * 0.3) * Math.min(w, h);
    ctx.fillStyle = "hsla(" + hues[Math.floor(rnd() * hues.length)] + ", " + (44 + rnd() * 22).toFixed(1) + "%, " + (38 + rnd() * 26).toFixed(1) + "%, .5)";
    ctx.beginPath(); ctx.arc(cx, cy, r, 0, Math.PI * 2); ctx.fill();
  }
  ctx.fillStyle = "rgba(255, 247, 230, .06)";
  for (let j = 0; j < h; j += 4) ctx.fillRect(0, j, w, 1);
}

export default function EmbedYoutubeResponsive() {
  const frameRef = useRef<HTMLDivElement>(null);
  const thumbRef = useRef<HTMLCanvasElement>(null);
  const readoutRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const frame = frameRef.current;
    const thumb = thumbRef.current;
    const readout = readoutRef.current;
    if (!frame || !thumb || !readout) return;

    drawSeedThumb(thumb, 101);

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    const narrow = window.matchMedia("(max-width: 340px)").matches;
    const BASE = narrow ? 140 : 200;
    const RANGE = narrow ? 36 : 56;

    function apply(t: number) {
      const w = BASE + RANGE * Math.sin((2 * Math.PI * t) / CYCLE_MS);
      frame!.style.width = w.toFixed(1) + "px";
      const rect = frame!.getBoundingClientRect();
      readout!.textContent = "16:9 · " + Math.round(w) + " × " + Math.round(rect.height) + "px";
    }

    apply(0);
    if (reduce) return;

    let start: number | null = null;
    let raf = 0;
    function loop(ts: number) {
      if (start === null) start = ts;
      const t = (ts - start) % CYCLE_MS;
      apply(t);
      raf = requestAnimationFrame(loop);
    }
    raf = requestAnimationFrame(loop);
    return () => cancelAnimationFrame(raf);
  }, []);

  return (
    <div className={styles.stage}>
      <section className={styles.panel}>
        <div className={styles.frame} ref={frameRef}>
          <canvas className={styles.thumb} ref={thumbRef} width={320} height={180} aria-hidden="true" />
          <div className={styles.playBtn} role="button" aria-label="재생">
            <svg className={styles.playIcon} viewBox="0 0 24 24" aria-hidden="true">
              <polygon points="7,4 20,12 7,20" />
            </svg>
          </div>
          <div className={styles.scrim}>
            <span className={styles.scrimTitle}>임베드 영상 미리보기</span>
            <span className={styles.scrimChannel}>Channel A</span>
          </div>
        </div>
        <div className={styles.readout} ref={readoutRef}>16:9 · 200 × 113px</div>
      </section>
    </div>
  );
}