01Input-popover value toggle — when an input's focus value turns on, a calendar unfolds as a popover, and folds away when it turns off

<main class="stage">
<div class="dp is-demo" id="dp">
  <button type="button" class="dp__field" id="dpField" aria-haspopup="dialog" aria-expanded="false">
    <span class="dp__fieldLabel">Check-in date</span>
    <span class="dp__fieldValue" id="dpValue">2026-03-14</span>
  </button>
  <div class="dp__pop" id="dpPop" role="dialog" aria-label="Calendar" aria-hidden="true">
    <div class="dp__head"><span class="dp__label">March 2026</span></div>
    <div class="dp__weekday" aria-hidden="true">
      <span>Sun</span><span>Mon</span><span>Tue</span><span>Wed</span><span>Thu</span><span>Fri</span><span>Sat</span>
    </div>
    <div class="dp__grid" id="dpGrid"></div>
  </div>
</div>
</main>

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

// 계산 겹: 팝오버 위치는 index.html measureAnchor() 의 getBoundingClientRect 실측값으로 정해진다.
// 애니메이션은 그 자리에서 transform(scale)·opacity 만 — top/left 는 실측 뒤 한 번만 세팅되고 트윈하지 않는다.
@include stage($stage-ink);

// 계산 겹: 팝오버가 필드 아래로 실제 높이만큼 펼쳐지므로 무대는 위쪽에 붙여
// 열림 상태의 전체 높이가 480x300·320x200 두 화면 모두에 들어가게 한다.
.stage {
  align-items: start;
  padding-top: $sp-4;
}

.dp {
  position: relative;
  width: 100%;
  max-width: 220px;
}

.dp__field {
  display: grid;
  gap: $sp-1;
  width: 100%;
  padding: $sp-2 $sp-3;
  border: none;
  border-radius: $r-control;
  background: $subject-blue-deep;
  color: $subject-cream;
  text-align: left;
  cursor: pointer;
  box-shadow: $shadow-raised;
}

.dp__fieldLabel {
  font-size: 10px;
  opacity: .8;
}

.dp__fieldValue {
  font-size: 14px;
  font-weight: 700;
}

.dp__pop {
  position: absolute;
  z-index: 2;
  box-sizing: border-box;
  padding: $sp-2;
  border-radius: $r-card;
  background: $stage-paper;
  box-shadow: $shadow-raised;
  transform-origin: top center;
  transform: scale(.85);
  opacity: 0;
  pointer-events: none;
  transition: transform $dur-enter $ease-elastic, opacity $dur-quick $ease-out;
}

.dp--open .dp__pop {
  transform: scale(1);
  opacity: 1;
  pointer-events: auto;
}

.dp__head {
  text-align: center;
  margin-bottom: $sp-1;
}

.dp__label {
  font-size: 11px;
  font-weight: 700;
  color: $subject-ink;
}

.dp__weekday,
.dp__grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
}

.dp__weekday span {
  font-size: 9px;
  text-align: center;
  color: rgba($subject-ink, .72);
  padding-bottom: $sp-1;
}

.dp__cell {
  display: grid;
  place-items: center;
  height: 21px;
  font-size: 11px;
  color: $subject-ink;
  border-radius: $r-xs;
}

.dp__cell--out {
  visibility: hidden;
}

.dp__cell--today {
  background: $subject-blue;
  color: $subject-cream;
  font-weight: 700;
}

@media (max-width: 340px) {
  .stage { padding-top: $sp-2; }
  .dp { max-width: 180px; }
  .dp__field { padding: $sp-1 $sp-2; }
  .dp__pop { padding: $sp-1; }
  .dp__cell { height: 17px; font-size: 10px; }
  .dp__weekday span { font-size: 8px; padding-bottom: 0; }
}

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

.stage {
  align-items: start;
  padding-top: 16px;
}

.dp {
  position: relative;
  width: 100%;
  max-width: 220px;
}

.dp__field {
  display: grid;
  gap: 4px;
  width: 100%;
  padding: 8px 12px;
  border: none;
  border-radius: 12px;
  background: #0a4fe8;
  color: #fff7e6;
  text-align: left;
  cursor: pointer;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.dp__fieldLabel {
  font-size: 10px;
  opacity: 0.8;
}

.dp__fieldValue {
  font-size: 14px;
  font-weight: 700;
}

.dp__pop {
  position: absolute;
  z-index: 2;
  box-sizing: border-box;
  padding: 8px;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform-origin: top center;
  transform: scale(0.85);
  opacity: 0;
  pointer-events: none;
  transition: transform 600ms cubic-bezier(0.34, 1.56, 0.64, 1), opacity 220ms ease-out;
}

.dp--open .dp__pop {
  transform: scale(1);
  opacity: 1;
  pointer-events: auto;
}

.dp__head {
  text-align: center;
  margin-bottom: 4px;
}

.dp__label {
  font-size: 11px;
  font-weight: 700;
  color: #17141a;
}

.dp__weekday,
.dp__grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
}

.dp__weekday span {
  font-size: 9px;
  text-align: center;
  color: rgba(23, 20, 26, 0.72);
  padding-bottom: 4px;
}

.dp__cell {
  display: grid;
  place-items: center;
  height: 21px;
  font-size: 11px;
  color: #17141a;
  border-radius: 4px;
}

.dp__cell--out {
  visibility: hidden;
}

.dp__cell--today {
  background: #2f6df6;
  color: #fff7e6;
  font-weight: 700;
}

@media (max-width: 340px) {
  .stage {
    padding-top: 8px;
  }
  .dp {
    max-width: 180px;
  }
  .dp__field {
    padding: 4px 8px;
  }
  .dp__pop {
    padding: 4px;
  }
  .dp__cell {
    height: 17px;
    font-size: 10px;
  }
  .dp__weekday span {
    font-size: 8px;
    padding-bottom: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .dp__pop {
    transition: none;
  }
}

(function () {
  var BASE = { y: 2026, m: 3, d: 14 }; // 계산 겹 상수: 고정 오늘(Mon 1~12), new Date() 미사용
  function isLeap(y) { return (y % 4 === 0 && y % 100 !== 0) || y % 400 === 0; }
  function daysInMonth(y, m) {
    var t = [31, isLeap(y) ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
    return t[m - 1];
  }
  function dow(y, m, d) { // Zeller 합동식 — 0=Sun ~ 6=Sat
    var yy = y, mm = m;
    if (mm < 3) { yy -= 1; mm += 12; }
    var K = yy % 100, J = Math.floor(yy / 100);
    var h = (d + Math.floor(13 * (mm + 1) / 5) + K + Math.floor(K / 4) + Math.floor(J / 4) - 2 * J) % 7;
    h = ((h % 7) + 7) % 7;
    return (h + 6) % 7;
  }

  var ANCHOR_GAP = 8; // 계산 겹: 필드 아래 팝오버 간격(px)
  var dp = document.getElementById('dp');
  var field = document.getElementById('dpField');
  var pop = document.getElementById('dpPop');
  var grid = document.getElementById('dpGrid');

  var n = daysInMonth(BASE.y, BASE.m);
  var lead = dow(BASE.y, BASE.m, 1);
  for (var i = 0; i < lead; i++) {
    var blank = document.createElement('span');
    blank.className = 'dp__cell dp__cell--out';
    grid.appendChild(blank);
  }
  for (var d = 1; d <= n; d++) {
    var cell = document.createElement('span');
    cell.className = 'dp__cell';
    cell.textContent = String(d);
    if (d === BASE.d) cell.classList.add('dp__cell--today');
    grid.appendChild(cell);
  }

  function measureAnchor() {
    // 계산 겹: 실측 위치 — 필드의 실제 렌더 폭·좌표를 읽어 팝오버를 그 자리에 앵커한다
    var fr = field.getBoundingClientRect();
    var pr = dp.getBoundingClientRect();
    pop.style.left = (fr.left - pr.left) + 'px';
    pop.style.top = (fr.bottom - pr.top + ANCHOR_GAP) + 'px';
    pop.style.width = fr.width + 'px';
  }

  function setOpen(v) {
    dp.classList.toggle('dp--open', v);
    field.setAttribute('aria-expanded', v ? 'true' : 'false');
    pop.setAttribute('aria-hidden', v ? 'false' : 'true');
    if (v) measureAnchor();
  }

  function human() {
    dp.classList.remove('is-demo');
    stopAutoplay();
    setOpen(!dp.classList.contains('dp--open'));
  }
  field.addEventListener('click', human);
  document.addEventListener('keydown', function (e) {
    if (e.key === 'Escape' && dp.classList.contains('dp--open')) { human(); }
  });
  document.addEventListener('click', function (e) {
    if (dp.classList.contains('dp--open') && !dp.contains(e.target)) { human(); }
  });

  var open = false;
  var autoTimer = null;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  setOpen(false);
  if (!reduce) {
    autoTimer = setInterval(function () {
      open = !open;
      setOpen(open);
    }, 1400);
  }
})();

import { useEffect, useRef, useState } from 'react';
import styles from './DatePickerPopoverOpen.module.scss';

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

const BASE = { y: 2026, m: 3, d: 14 }; // 계산 겹 상수: 고정 오늘(월 1~12), new Date() 미사용
const ANCHOR_GAP = 8; // 계산 겹: 필드 아래 팝오버 간격(px)
const WEEKDAY = ['일', '월', '화', '수', '목', '금', '토'];

function isLeap(y: number) {
  return (y % 4 === 0 && y % 100 !== 0) || y % 400 === 0;
}

function daysInMonth(y: number, m: number) {
  const t = [31, isLeap(y) ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
  return t[m - 1];
}

function dow(y: number, m: number, d: number) { // Zeller 합동식 — 0=일 ~ 6=토
  let yy = y;
  let mm = m;
  if (mm < 3) { yy -= 1; mm += 12; }
  const K = yy % 100;
  const J = Math.floor(yy / 100);
  let h = (d + Math.floor((13 * (mm + 1)) / 5) + K + Math.floor(K / 4) + Math.floor(J / 4) - 2 * J) % 7;
  h = ((h % 7) + 7) % 7;
  return (h + 6) % 7;
}

function buildCells() {
  const n = daysInMonth(BASE.y, BASE.m);
  const lead = dow(BASE.y, BASE.m, 1);
  const cells: { key: string; d: number | null; today: boolean }[] = [];
  for (let i = 0; i < lead; i++) cells.push({ key: 'out' + i, d: null, today: false });
  for (let d = 1; d <= n; d++) cells.push({ key: 'd' + d, d, today: d === BASE.d });
  return cells;
}

export default function DatePickerPopoverOpen() {
  const rootRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const fieldRef = useRef(null) as unknown as Box<HTMLButtonElement>;
  const popRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const [isDemo, setIsDemo] = useState(true);
  const [open, setOpen] = useState(false);
  const cells = buildCells();

  function measureAnchor() {
    // 계산 겹: 실측 위치 — 필드의 실제 렌더 폭·좌표를 읽어 팝오버를 그 자리에 앵커한다
    const field = fieldRef.current;
    const root = rootRef.current;
    const pop = popRef.current;
    if (!field || !root || !pop) return;
    const fr = field.getBoundingClientRect();
    const pr = root.getBoundingClientRect();
    pop.style.left = fr.left - pr.left + 'px';
    pop.style.top = fr.bottom - pr.top + ANCHOR_GAP + 'px';
    pop.style.width = fr.width + 'px';
  }

  function human() {
    setIsDemo(false);
    setOpen((v) => !v);
  }

  useEffect(() => {
    if (open) measureAnchor();
  }, [open]);

  useEffect(() => {
    function onKey(e: KeyboardEvent) {
      if (e.key === 'Escape' && open) human();
    }
    function onDoc(e: MouseEvent) {
      const root = rootRef.current;
      if (open && root && !root.contains(e.target as Node)) human();
    }
    document.addEventListener('keydown', onKey);
    document.addEventListener('click', onDoc);
    return () => {
      document.removeEventListener('keydown', onKey);
      document.removeEventListener('click', onDoc);
    };
  }, [open]);

  useEffect(() => {
    const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    if (!isDemo || reduce) return;
    const timer = window.setInterval(() => {
      setOpen((v) => !v);
    }, 1400);
    return () => window.clearInterval(timer);
  }, [isDemo]);

  return (
    <div className={`${styles.dp} ${isDemo ? styles.isDemo : ''} ${open ? styles.dpOpen : ''}`} ref={rootRef}>
      <button
        type="button"
        className={styles.dpField}
        ref={fieldRef}
        aria-haspopup="dialog"
        aria-expanded={open}
        onClick={human}
      >
        <span className={styles.dpFieldLabel}>체크인 날짜</span>
        <span className={styles.dpFieldValue}>2026-03-14</span>
      </button>
      <div className={styles.dpPop} ref={popRef} role="dialog" aria-label="달력" aria-hidden={!open}>
        <div className={styles.dpHead}><span className={styles.dpLabel}>2026년 3월</span></div>
        <div className={styles.dpWeekday} aria-hidden="true">
          {WEEKDAY.map((w) => <span key={w}>{w}</span>)}
        </div>
        <div className={styles.dpGrid}>
          {cells.map((c) => (
            <span
              key={c.key}
              className={`${styles.dpCell} ${c.d === null ? styles.dpCellOut : ''} ${c.today ? styles.dpCellToday : ''}`}
            >
              {c.d ?? ''}
            </span>
          ))}
        </div>
      </div>
    </div>
  );
}