04Magic link — a sent-confirmation card that recomputes remaining time into a ring's arc length

<main class="stage">
<section class="card">
  <p class="eyebrow">Magic link sent</p>
  <p class="recipient">Sent to [email protected]</p>
  <div class="ringWrap">
    <svg class="ringSvg" viewBox="0 0 96 96" aria-hidden="true">
      <circle class="ringTrack" cx="48" cy="48" r="44"></circle>
      <circle class="ringProgress" id="magicRing" cx="48" cy="48" r="44" stroke-dasharray="276.46" stroke-dashoffset="0"></circle>
    </svg>
    <p class="time" id="magicTime">Time left 300s</p>
  </div>
  <p class="hint">Request a new one if it expires</p>
</section>
</main>

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

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

@include stage($stage-paper);

.card {
  position: relative;
  width: 100%;
  max-width: 320px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
  text-align: center;
  padding: $sp-6;
  border-radius: $r-card;
  background: $stage-paper;
  box-shadow: $shadow-raised;
}

.eyebrow {
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba($color, .12);
  color: $color;
  font-weight: 600;
  font-size: 11px;
  letter-spacing: .04em;
}

.recipient {
  margin: 0;
  color: $subject-ink;
  font-weight: 400;
  font-size: 13px;
  opacity: .78;
}

.ringWrap {
  position: relative;
  width: 96px;
  height: 96px;
  display: grid;
  place-items: center;
}

.ringSvg {
  width: 96px;
  height: 96px;
  // 12시 방향에서 시작하도록 회전한다 — scale 이 아니라 rotate 라 transform-origin 기본(center)으로 충분
  transform: rotate(-90deg);
}

.ringTrack {
  fill: none;
  stroke: rgba($subject-ink, .12);
  stroke-width: 8px;
}

.ringProgress {
  fill: none;
  stroke: $color;
  stroke-width: 8px;
  stroke-linecap: round;
}

.time {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  margin: 0;
  color: $subject-ink;
  font-weight: 700;
  font-size: 18px;
  line-height: 1.2;
}

.hint {
  margin: 0;
  color: $subject-ink;
  opacity: .72;
  font-weight: 400;
  font-size: 12px;
  line-height: 1.4;
}

@media (max-width: 340px) {
  .card { max-width: 240px; padding: $sp-3; gap: $sp-1; }
  .eyebrow { font-size: 10px; padding: $sp-1 $sp-2; }
  .recipient { font-size: 11px; }
  .ringWrap, .ringSvg { width: 64px; height: 64px; }
  .ringTrack, .ringProgress { stroke-width: 6px; }
  .time { font-size: 12px; }
  .hint { font-size: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  .ringProgress { transition: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.card {
  position: relative;
  width: 100%;
  max-width: 320px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  text-align: center;
  padding: 24px;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.eyebrow {
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(10, 79, 232, 0.12);
  color: #0a4fe8;
  font-weight: 600;
  font-size: 11px;
  letter-spacing: 0.04em;
}

.recipient {
  margin: 0;
  color: #17141a;
  font-weight: 400;
  font-size: 13px;
  opacity: 0.78;
}

.ringWrap {
  position: relative;
  width: 96px;
  height: 96px;
  display: grid;
  place-items: center;
}

.ringSvg {
  width: 96px;
  height: 96px;
  transform: rotate(-90deg);
}

.ringTrack {
  fill: none;
  stroke: rgba(23, 20, 26, 0.12);
  stroke-width: 8px;
}

.ringProgress {
  fill: none;
  stroke: #0a4fe8;
  stroke-width: 8px;
  stroke-linecap: round;
}

.time {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  margin: 0;
  color: #17141a;
  font-weight: 700;
  font-size: 18px;
  line-height: 1.2;
}

.hint {
  margin: 0;
  color: #17141a;
  opacity: 0.72;
  font-weight: 400;
  font-size: 12px;
  line-height: 1.4;
}

@media (max-width: 340px) {
  .card {
    max-width: 240px;
    padding: 12px;
    gap: 4px;
  }
  .eyebrow {
    font-size: 10px;
    padding: 4px 8px;
  }
  .recipient {
    font-size: 11px;
  }
  .ringWrap, .ringSvg {
    width: 64px;
    height: 64px;
  }
  .ringTrack, .ringProgress {
    stroke-width: 6px;
  }
  .time {
    font-size: 12px;
  }
  .hint {
    font-size: 10px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ringProgress {
    transition: none;
  }
}

// 매직 링크(04) — 발송 시각으로부터 남은 유효시간을 매 프레임 새로 구해(누적하지 않음)
// 그 비율만큼 SVG 링의 stroke-dashoffset 을 다시 그린다. CSS keyframes 없이 rAF 로만 진행해
// 캡처 창(2s) 전체가 실제 경과 시간대로 기록되게 한다.
(function () {
  var ring = document.getElementById('magicRing');
  var timeText = document.getElementById('magicTime');
  if (!ring || !timeText) return;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var VALID_SEC = 300; // 변형: 300 → 900
  var CIRCUMFERENCE = 276.46;
  var CYCLE_MS = 2000;

  function ratio(t) {
    return 1 - Math.min(Math.max(t / CYCLE_MS, 0), 1);
  }

  function apply(t) {
    var r = ratio(t);
    var remainingDisplaySec = Math.ceil(r * VALID_SEC);
    ring.style.strokeDashoffset = String(CIRCUMFERENCE * (1 - r));
    timeText.textContent = 'Time left' + ' ' + remainingDisplaySec + 's';
  }

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

  if (reduce) {
    apply(0);
  } else {
    requestAnimationFrame(frame);
  }
})();

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

// 매직 링크(04) — 발송 시각으로부터 남은 유효시간을 매 프레임 새로 구해(누적하지 않음)
// 그 비율만큼 SVG 링의 stroke-dashoffset 을 다시 그린다. CSS keyframes 없이 rAF 로만 진행한다.
const VALID_SEC = 300; // 변형: 300 → 900
const CIRCUMFERENCE = 276.46;
const CYCLE_MS = 2000;

function ratio(t: number): number {
  return 1 - Math.min(Math.max(t / CYCLE_MS, 0), 1);
}

export default function MagicLink() {
  const ringRef = useRef<SVGCircleElement>(null);
  const timeRef = useRef<HTMLParagraphElement>(null);

  useEffect(() => {
    const ring = ringRef.current;
    const timeText = timeRef.current;
    if (!ring || !timeText) return;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    function apply(t: number) {
      const r = ratio(t);
      const remainingDisplaySec = Math.ceil(r * VALID_SEC);
      if (ring) ring.style.strokeDashoffset = String(CIRCUMFERENCE * (1 - r));
      if (timeText) timeText.textContent = "남은 시간" + " " + remainingDisplaySec + "초";
    }

    let start: number | null = null;
    let raf = 0;
    function frame(ts: number) {
      if (start === null) start = ts;
      const t = (ts - start) % CYCLE_MS;
      apply(t);
      raf = requestAnimationFrame(frame);
    }

    if (reduce) {
      apply(0);
    } else {
      raf = requestAnimationFrame(frame);
    }

    return () => {
      if (raf) cancelAnimationFrame(raf);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <section className={styles.card}>
        <p className={styles.eyebrow}>매직 링크 발송 완료</p>
        <p className={styles.recipient}>[email protected] 으로 전송됨</p>
        <div className={styles.ringWrap}>
          <svg className={styles.ringSvg} viewBox="0 0 96 96" aria-hidden="true">
            <circle className={styles.ringTrack} cx={48} cy={48} r={44} />
            <circle
              ref={ringRef}
              className={styles.ringProgress}
              cx={48}
              cy={48}
              r={44}
              strokeDasharray={276.46}
              strokeDashoffset={0}
            />
          </svg>
          <p className={styles.time} ref={timeRef}>
            남은 시간 300초
          </p>
        </div>
        <p className={styles.hint}>만료되면 다시 요청해 주세요</p>
      </section>
    </main>
  );
}