03Dynamic viewport height — a full-screen height that re-measures as the address bar resizes

<main class="stage">
<div class="wrap is-demo" id="wrap">
  <button class="addrToggle" id="addrToggle" type="button" aria-pressed="false">Collapse bar</button>
  <div class="phones">
    <div class="phone">
      <span class="phoneLabel">Fixed 100vh</span>
      <div class="screen" id="screenFixed">
        <div class="addressBar" id="addressBarFixed"></div>
        <button class="anchor is-fixed" id="anchorFixed" type="button">Continue</button>
      </div>
    </div>
    <div class="phone">
      <span class="phoneLabel">Dynamic viewport</span>
      <div class="screen" id="screenDvh">
        <div class="addressBar" id="addressBarDvh"></div>
        <button class="anchor is-dvh" id="anchorDvh" type="button">Continue</button>
      </div>
    </div>
  </div>
</div>
</main>

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

// 계산 겹은 index.html 의 recalc()/scheduleRecalc() 에 있다 — 주소창 상태가 바뀌면 VH_RECALC_DEBOUNCE_MS
// 뒤에야 --bar-h 커스텀 속성이 갱신된다(실제 동적 뷰포트 재계산의 지연을 흉내). 여기는 두 판(고정·동적)의
// 프레임 모양과, --bar-h 를 transform 으로 반영하는 규칙만 맡는다.
@include stage($stage-ink);

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

.addrToggle {
  appearance: none;
  border: none;
  border-radius: $r-pill;
  background: $subject-blue;
  color: $subject-cream;
  padding: $sp-1 $sp-4;
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  transition: transform $dur-instant $ease-out;

  &:hover { transform: translateY(-1px); }
  &:active { transform: scale(.95); }
  &:focus-visible { outline: 2px solid $subject-blue-light; outline-offset: 2px; }
}

.phones {
  display: flex;
  gap: $sp-4;
}

.phone {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-1;
}

.phoneLabel {
  color: $subject-cream;
  font-size: 10px;
  font-weight: 600;
}

.screen {
  position: relative;
  width: 96px;
  height: 148px;
  border-radius: $r-sm;
  overflow: hidden;
  background: rgba($subject-cream, .08);
  box-shadow: inset 0 0 0 2px rgba($subject-cream, .18);
}

.addressBar {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 26px;
  background: $subject-blue-deep;
  transform: translateY(0);
  transition: transform $dur-base $ease-out;
  z-index: 2;
}

.is-collapsed .addressBar { transform: translateY(100%); }

.anchor {
  position: absolute;
  left: 8px;
  right: 8px;
  bottom: 8px;
  padding: $sp-1 0;
  border: none;
  border-radius: $r-xs;
  background: $subject-pink;
  color: $subject-ink;
  font-size: 9px;
  font-weight: 700;
  cursor: pointer;
}

// 고정판: 100vh 만 아는 환경 — 주소창이 접히고 펼쳐져도 버튼이 다시 계산되지 않는다(버그 그대로 재현)
.anchor.is-fixed {
  z-index: 1;
  transform: translateY(0);
}

// 동적 뷰포트판: dvh 를 아는 환경 — --bar-h 만큼 위로 밀어 올려 항상 주소창 위에 머문다
.anchor.is-dvh {
  z-index: 2;
  transform: translateY(calc(-1 * var(--bar-h, 0px)));
  transition: transform $dur-base $ease-out;
  opacity: .5;
}

.anchor.is-dvh.is-settled { opacity: 1; }

@media (max-width: 340px) {
  .wrap { gap: $sp-1; }
  .phones { gap: $sp-2; }
  .screen { width: 72px; height: 104px; }
  .addressBar { height: 20px; }
  .anchor { font-size: 8px; }
}

@media (prefers-reduced-motion: reduce) {
  .addressBar { transition: none; }
  .anchor.is-dvh { transition: none; }
  .addrToggle { 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);
}

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

.addrToggle {
  appearance: none;
  border: none;
  border-radius: 999px;
  background: #2f6df6;
  color: #fff7e6;
  padding: 4px 16px;
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 140ms ease-out;
}
.addrToggle:hover {
  transform: translateY(-1px);
}
.addrToggle:active {
  transform: scale(0.95);
}
.addrToggle:focus-visible {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.phones {
  display: flex;
  gap: 16px;
}

.phone {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.phoneLabel {
  color: #fff7e6;
  font-size: 10px;
  font-weight: 600;
}

.screen {
  position: relative;
  width: 96px;
  height: 148px;
  border-radius: 8px;
  overflow: hidden;
  background: rgba(255, 247, 230, 0.08);
  box-shadow: inset 0 0 0 2px rgba(255, 247, 230, 0.18);
}

.addressBar {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 26px;
  background: #0a4fe8;
  transform: translateY(0);
  transition: transform 300ms ease-out;
  z-index: 2;
}

.is-collapsed .addressBar {
  transform: translateY(100%);
}

.anchor {
  position: absolute;
  left: 8px;
  right: 8px;
  bottom: 8px;
  padding: 4px 0;
  border: none;
  border-radius: 4px;
  background: #ff9ebb;
  color: #17141a;
  font-size: 9px;
  font-weight: 700;
  cursor: pointer;
}

.anchor.is-fixed {
  z-index: 1;
  transform: translateY(0);
}

.anchor.is-dvh {
  z-index: 2;
  transform: translateY(calc(-1 * var(--bar-h, 0px)));
  transition: transform 300ms ease-out;
  opacity: 0.5;
}

.anchor.is-dvh.is-settled {
  opacity: 1;
}

@media (max-width: 340px) {
  .wrap {
    gap: 4px;
  }
  .phones {
    gap: 8px;
  }
  .screen {
    width: 72px;
    height: 104px;
  }
  .addressBar {
    height: 20px;
  }
  .anchor {
    font-size: 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .addressBar {
    transition: none;
  }
  .anchor.is-dvh {
    transition: none;
  }
  .addrToggle {
    transition: none;
  }
}

(function () {
  var VH_RECALC_DEBOUNCE_MS = 150; // 주소창이 움직인 뒤 높이를 다시 계산하기까지의 지연 — 변형 목표: 150 → 50
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var wrap = document.getElementById('wrap');
  var addrToggle = document.getElementById('addrToggle');
  var screenDvh = document.getElementById('screenDvh');
  var anchorDvh = document.getElementById('anchorDvh');
  var isDemo = true;

  var BAR_OPEN_PX = 34; // 주소창이 펼쳐졌을 때 화면에서 차지하는 높이
  var timer = null;
  var collapsed = false;

  function human() { if (isDemo) { wrap.classList.remove('is-demo'); isDemo = false; } }

  function recalc() {
    var barH = collapsed ? 0 : BAR_OPEN_PX;
    // 동적 뷰포트판만 다시 잰다 — 100vh 고정판은 실제로 재계산을 안 하는 버그를 그대로 보여준다
    screenDvh.style.setProperty('--bar-h', barH + 'px');
    anchorDvh.classList.add('is-settled');
  }

  function scheduleRecalc() {
    anchorDvh.classList.remove('is-settled');
    if (timer) clearTimeout(timer);
    timer = setTimeout(recalc, VH_RECALC_DEBOUNCE_MS);
  }

  function setCollapsed(on) {
    collapsed = on;
    wrap.classList.toggle('is-collapsed', on);
    addrToggle.textContent = on ? 'Expand bar' : 'Collapse bar';
    addrToggle.setAttribute('aria-pressed', String(on));
    scheduleRecalc();
  }

  addrToggle.addEventListener('click', function () { human(); setCollapsed(!collapsed); });
  addrToggle.addEventListener('keydown', function (e) {
    if (e.key === 'Enter' || e.key === ' ') human();
  });

  recalc();

  var last = 0;
  var STEP_MS = 780;
  function loop(ts) {
    if (!last) last = ts;
    if (isDemo && !reduce && ts - last >= STEP_MS) {
      last = ts;
      setCollapsed(!collapsed);
    }
    requestAnimationFrame(loop);
  }
  requestAnimationFrame(loop);
})();

// DvhMobileViewport — vanilla 판(run/375/demo/03-compat-100vh-mobile-dvh/index.html) 의 React 포트.
// 100vh 고정판은 주소창이 접히고 펼쳐져도 재계산하지 않는 버그를 그대로 보여주고, 동적 뷰포트판은
// VH_RECALC_DEBOUNCE_MS 뒤에 --bar-h 를 다시 놓는다.
import { useEffect, useRef } from "react";
import styles from "./DvhMobileViewport.module.scss";

type Box<T> = { current: T };

const VH_RECALC_DEBOUNCE_MS = 150; // 주소창이 움직인 뒤 높이를 다시 계산하기까지의 지연 — 변형 목표: 150 → 50
const BAR_OPEN_PX = 34; // 주소창이 펼쳐졌을 때 화면에서 차지하는 높이
const STEP_MS = 780;

export default function DvhMobileViewport() {
  const rootRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const addrToggleRef = useRef(null) as unknown as Box<HTMLButtonElement>;
  const screenDvhRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const anchorDvhRef = useRef(null) as unknown as Box<HTMLButtonElement>;
  const rafRef = useRef(0) as unknown as Box<number>;
  const timerRef = useRef(0) as unknown as Box<number>;

  useEffect(() => {
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    const wrap = rootRef.current;
    const addrToggle = addrToggleRef.current;
    const screenDvh = screenDvhRef.current;
    const anchorDvh = anchorDvhRef.current;
    if (!wrap || !addrToggle || !screenDvh || !anchorDvh) return;

    let isDemo = true;
    let collapsed = false;

    function human() { if (isDemo) { wrap!.classList.remove(styles.isDemo); isDemo = false; } }

    function recalc() {
      const barH = collapsed ? 0 : BAR_OPEN_PX;
      screenDvh!.style.setProperty("--bar-h", barH + "px");
      anchorDvh!.classList.add(styles.isSettled);
    }
    function scheduleRecalc() {
      anchorDvh!.classList.remove(styles.isSettled);
      window.clearTimeout(timerRef.current);
      timerRef.current = window.setTimeout(recalc, VH_RECALC_DEBOUNCE_MS);
    }
    function setCollapsed(on: boolean) {
      collapsed = on;
      wrap!.classList.toggle(styles.isCollapsed, on);
      addrToggle!.textContent = on ? "주소창 펼치기" : "주소창 접기";
      addrToggle!.setAttribute("aria-pressed", String(on));
      scheduleRecalc();
    }
    function onClick() { human(); setCollapsed(!collapsed); }
    function onKeyDown(e: KeyboardEvent) { if (e.key === "Enter" || e.key === " ") human(); }
    addrToggle.addEventListener("click", onClick);
    addrToggle.addEventListener("keydown", onKeyDown);

    recalc();

    let last = 0;
    function loop(ts: number) {
      if (!last) last = ts;
      if (isDemo && !reduce && ts - last >= STEP_MS) {
        last = ts;
        setCollapsed(!collapsed);
      }
      rafRef.current = requestAnimationFrame(loop);
    }
    rafRef.current = requestAnimationFrame(loop);

    return () => {
      addrToggle!.removeEventListener("click", onClick);
      addrToggle!.removeEventListener("keydown", onKeyDown);
      window.clearTimeout(timerRef.current);
      cancelAnimationFrame(rafRef.current);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.wrap + " " + styles.isDemo} ref={rootRef}>
        <button className={styles.addrToggle} ref={addrToggleRef} type="button" aria-pressed="false">주소창 접기</button>
        <div className={styles.phones}>
          <div className={styles.phone}>
            <span className={styles.phoneLabel}>100vh 고정판</span>
            <div className={styles.screen}>
              <div className={styles.addressBar}></div>
              <button className={styles.anchor + " " + styles.isFixed} type="button">계속하기</button>
            </div>
          </div>
          <div className={styles.phone}>
            <span className={styles.phoneLabel}>동적 뷰포트판</span>
            <div className={styles.screen} ref={screenDvhRef}>
              <div className={styles.addressBar}></div>
              <button className={styles.anchor + " " + styles.isDvh} ref={anchorDvhRef} type="button">계속하기</button>
            </div>
          </div>
        </div>
      </div>
    </main>
  );
}