04Anchored price stack

<main class="stage is-demo">
  <section class="ap">
    <header class="ap__head">
      <span class="ap__ic" aria-hidden="true"><svg viewBox="0 0 256 256" width="20" height="20"><g fill="currentColor"><path d="M237.66 153L153 237.66a8 8 0 0 1-11.31 0l-99.35-99.32a8 8 0 0 1-2.34-5.65V40h92.69a8 8 0 0 1 5.65 2.34l99.32 99.32a8 8 0 0 1 0 11.34" opacity=".2"/><path d="M243.31 136L144 36.69A15.86 15.86 0 0 0 132.69 32H40a8 8 0 0 0-8 8v92.69A15.86 15.86 0 0 0 36.69 144L136 243.31a16 16 0 0 0 22.63 0l84.68-84.68a16 16 0 0 0 0-22.63m-96 96L48 132.69V48h84.69L232 147.31ZM96 84a12 12 0 1 1-12-12a12 12 0 0 1 12 12"/></g></svg></span>
      <div class="ap__tt">
        <p class="ap__plan">Starter plan</p>
        <p class="ap__sub">See your first-month price</p>
      </div>
    </header>
    <button type="button" class="ap__toggle" aria-expanded="false" aria-controls="ap-panel">
      <span class="ap__toggle-t">See price breakdown</span>
      <svg class="ap__chev" viewBox="0 0 24 24" width="12" height="12" aria-hidden="true"><polyline points="6 9 12 15 18 9" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round"/></svg>
    </button>
    <div class="ap__panel" id="ap-panel">
      <div class="ap__panel-in">
        <ul class="ap__stack">
          <li class="ap__row" style="--i:0">
            <span class="ap__label">List price</span>
            <span class="ap__orig">₩59,000<span class="ap__strike" aria-hidden="true"></span></span>
          </li>
          <li class="ap__row" style="--i:1">
            <span class="ap__label">First-month price</span>
            <b class="ap__deal">₩29,000</b>
          </li>
          <li class="ap__row" style="--i:2">
            <span class="ap__label">With coupon</span>
            <span class="ap__final">₩20,300</span>
          </li>
          <li class="ap__row ap__row--save" style="--i:3">
            <span class="ap__save">Save ₩38,700</span>
          </li>
        </ul>
      </div>
    </div>
  </section>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;
$easing: $ease-pop;
$color: $subject-blue;

@include stage($stage-paper);

.ap {
  width: min(300px, 94vw);
  box-sizing: border-box;
  background: $stage-paper;
  border: 1px solid rgba(23, 20, 26, .1);
  border-radius: $r-card;
  box-shadow: $shadow-press;
  padding: $sp-4;
}

.ap__head { display: flex; align-items: center; gap: $sp-2; }
.ap__ic { display: grid; place-items: center; flex: 0 0 auto; color: $color; }
.ap__tt { display: flex; flex-direction: column; font-family: inherit; }
.ap__plan { margin: 0; font-weight: 800; font-size: 13px; line-height: 1.2; color: $subject-ink; }
.ap__sub { margin: 0; font-weight: 500; font-size: 11px; line-height: 1.4; color: rgba(23, 20, 26, .72); }

// ── 토글 버튼 ────────────────────────────────────────
.ap__toggle {
  display: flex; align-items: center; justify-content: center; gap: $sp-1;
  width: 100%; margin-top: $sp-3;
  padding: $sp-2 $sp-3;
  border: 1.5px solid rgba(47, 109, 246, .28);
  border-radius: $r-control;
  background: rgba(47, 109, 246, .08);
  color: $subject-blue-deep;   // 연파랑 면 위 파란 글자 4.10:1 → deep 5.78:1
  font-family: inherit; font-weight: 800; font-size: 12px; line-height: 1;
  cursor: pointer;
}
.ap__toggle:focus-visible { outline: 2px solid $subject-blue; outline-offset: 2px; }
.ap__chev { transition: transform $dur-base $easing; }
.ap.is-open .ap__chev { transform: rotate(180deg); }

// ── 펼침 패널 (grid 0fr → 1fr) ───────────────────────
.ap__panel { display: grid; grid-template-rows: 0fr; transition: grid-template-rows $dur-base $easing; }
.ap.is-open .ap__panel { grid-template-rows: 1fr; }
.ap__panel-in { overflow: hidden; }

.ap__stack { list-style: none; margin: 0; padding: $sp-3 0 0; display: flex; flex-direction: column; gap: $sp-2; }
.ap__row {
  display: flex; align-items: baseline; justify-content: space-between; gap: $sp-2;
  font-family: inherit;
}
.ap__label { font-weight: 600; font-size: 11px; line-height: 1.2; color: rgba(23, 20, 26, .72); }

.ap__orig { position: relative; font-weight: 600; font-size: 13px; line-height: 1.2; color: rgba(23, 20, 26, .72); }
.ap__strike {
  position: absolute; left: 0; right: 0; top: 50%; height: 2px;
  background: $error; border-radius: 0;
  transform: scaleX(0); transform-origin: left center; // 규칙8: 좌변서 그어짐
  transition: transform $dur-base $easing;
}
.ap.is-open .ap__strike { transform: scaleX(1); }

.ap__deal { font-weight: 800; font-size: 22px; line-height: 1.1; color: $color; font-variant-numeric: tabular-nums; }
.ap__final { font-weight: 800; font-size: 15px; line-height: 1.2; color: $subject-ink; font-variant-numeric: tabular-nums; }

.ap__row--save { justify-content: flex-end; }
.ap__save {
  display: inline-block;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: $error; color: $subject-cream;
  font-weight: 800; font-size: 11px; line-height: 1.3;
}

// ── 측정용 루프 (.is-demo) ───────────────────────────
// 패널을 펼친 채로 네 줄이 시차 등장하고, 90% 지점에서 컷으로 되돌아 다음 바퀴를 돈다.
.stage.is-demo .ap__panel { grid-template-rows: 1fr; }
.stage.is-demo .ap__chev { transform: rotate(180deg); }

.stage.is-demo .ap__row {
  animation-name: ap-rise;
  animation-duration: $duration;
  animation-timing-function: $easing;
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: calc(var(--i) * 80ms);
}
// 마지막 줄(--i:3, 지연 240ms)까지 2s 루프의 90% 안에 되돌아오도록 78% 에서 컷
@keyframes ap-rise {
  0%        { opacity: 0; transform: translateY(10px); }
  12%       { opacity: 1; transform: translateY(0); }
  74%       { opacity: 1; transform: translateY(0); }
  78%, 100% { opacity: 0; transform: translateY(10px); }
}

.stage.is-demo .ap__strike {
  transition: none;
  animation-name: ap-strike;
  animation-duration: $duration;
  animation-timing-function: $ease-out;
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: 120ms;
}
@keyframes ap-strike {
  0%        { transform: scaleX(0); }
  24%, 74%  { transform: scaleX(1); }
  78%, 100% { transform: scaleX(0); }
}

.stage.is-demo .ap__save {
  animation-name: ap-pop;
  animation-duration: $duration;
  animation-timing-function: $easing;
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: 240ms;
}
@keyframes ap-pop {
  0%        { transform: scale(.6); }
  18%       { transform: scale(1.14); }
  28%, 74%  { transform: scale(1); }
  78%, 100% { transform: scale(.6); }
}

// ── 접근성 ──────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .ap__panel, .ap__chev, .ap__strike { transition: none !important; }
  .stage.is-demo .ap__row,
  .stage.is-demo .ap__strike,
  .stage.is-demo .ap__save { animation: none !important; }
  .stage.is-demo .ap__row { opacity: 1 !important; transform: none !important; }
  .stage.is-demo .ap__strike { transform: scaleX(1) !important; }
  .stage.is-demo .ap__save { transform: none !important; }
}

// ── 반응형(320×200) ──────────────────────────────────
@media (max-width: 340px), (max-height: 220px) {
  .ap { width: min(268px, 92vw); padding: $sp-2; }
  .ap__ic svg { width: 16px; height: 16px; }
  .ap__plan { font-size: 11px; }
  .ap__sub { font-size: 9px; }
  .ap__toggle { margin-top: $sp-2; padding: $sp-1 $sp-2; font-size: 10px; }
  .ap__stack { padding: $sp-2 0 0; gap: $sp-1; }
  .ap__label { font-size: 9px; }
  .ap__orig { font-size: 11px; }
  .ap__deal { font-size: 17px; }
  .ap__final { font-size: 12px; }
  .ap__save { padding: 0 $sp-2; font-size: 9px; }
}

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);
}

.ap {
  width: min(300px, 94vw);
  box-sizing: border-box;
  background: #ffffff;
  border: 1px solid rgba(23, 20, 26, 0.1);
  border-radius: 16px;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  padding: 16px;
}

.ap__head {
  display: flex;
  align-items: center;
  gap: 8px;
}

.ap__ic {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  color: #2f6df6;
}

.ap__tt {
  display: flex;
  flex-direction: column;
  font-family: inherit;
}

.ap__plan {
  margin: 0;
  font-weight: 800;
  font-size: 13px;
  line-height: 1.2;
  color: #17141a;
}

.ap__sub {
  margin: 0;
  font-weight: 500;
  font-size: 11px;
  line-height: 1.4;
  color: rgba(23, 20, 26, 0.72);
}

.ap__toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  width: 100%;
  margin-top: 12px;
  padding: 8px 12px;
  border: 1.5px solid rgba(47, 109, 246, 0.28);
  border-radius: 12px;
  background: rgba(47, 109, 246, 0.08);
  color: #0a4fe8;
  font-family: inherit;
  font-weight: 800;
  font-size: 12px;
  line-height: 1;
  cursor: pointer;
}

.ap__toggle:focus-visible {
  outline: 2px solid #2f6df6;
  outline-offset: 2px;
}

.ap__chev {
  transition: transform 300ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.ap.is-open .ap__chev {
  transform: rotate(180deg);
}

.ap__panel {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 300ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.ap.is-open .ap__panel {
  grid-template-rows: 1fr;
}

.ap__panel-in {
  overflow: hidden;
}

.ap__stack {
  list-style: none;
  margin: 0;
  padding: 12px 0 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.ap__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  font-family: inherit;
}

.ap__label {
  font-weight: 600;
  font-size: 11px;
  line-height: 1.2;
  color: rgba(23, 20, 26, 0.72);
}

.ap__orig {
  position: relative;
  font-weight: 600;
  font-size: 13px;
  line-height: 1.2;
  color: rgba(23, 20, 26, 0.72);
}

.ap__strike {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 2px;
  background: #c2361a;
  border-radius: 0;
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 300ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.ap.is-open .ap__strike {
  transform: scaleX(1);
}

.ap__deal {
  font-weight: 800;
  font-size: 22px;
  line-height: 1.1;
  color: #2f6df6;
  font-variant-numeric: tabular-nums;
}

.ap__final {
  font-weight: 800;
  font-size: 15px;
  line-height: 1.2;
  color: #17141a;
  font-variant-numeric: tabular-nums;
}

.ap__row--save {
  justify-content: flex-end;
}

.ap__save {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 999px;
  background: #c2361a;
  color: #fff7e6;
  font-weight: 800;
  font-size: 11px;
  line-height: 1.3;
}

.stage.is-demo .ap__panel {
  grid-template-rows: 1fr;
}

.stage.is-demo .ap__chev {
  transform: rotate(180deg);
}

.stage.is-demo .ap__row {
  animation-name: ap-rise;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 1.4, 0.4, 1);
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: calc(var(--i) * 80ms);
}

@keyframes ap-rise {
  0% {
    opacity: 0;
    transform: translateY(10px);
  }
  12% {
    opacity: 1;
    transform: translateY(0);
  }
  74% {
    opacity: 1;
    transform: translateY(0);
  }
  78%, 100% {
    opacity: 0;
    transform: translateY(10px);
  }
}
.stage.is-demo .ap__strike {
  transition: none;
  animation-name: ap-strike;
  animation-duration: 2s;
  animation-timing-function: ease-out;
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: 120ms;
}

@keyframes ap-strike {
  0% {
    transform: scaleX(0);
  }
  24%, 74% {
    transform: scaleX(1);
  }
  78%, 100% {
    transform: scaleX(0);
  }
}
.stage.is-demo .ap__save {
  animation-name: ap-pop;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 1.4, 0.4, 1);
  animation-iteration-count: infinite;
  animation-fill-mode: backwards;
  animation-delay: 240ms;
}

@keyframes ap-pop {
  0% {
    transform: scale(0.6);
  }
  18% {
    transform: scale(1.14);
  }
  28%, 74% {
    transform: scale(1);
  }
  78%, 100% {
    transform: scale(0.6);
  }
}
@media (prefers-reduced-motion: reduce) {
  .ap__panel, .ap__chev, .ap__strike {
    transition: none !important;
  }
  .stage.is-demo .ap__row,
  .stage.is-demo .ap__strike,
  .stage.is-demo .ap__save {
    animation: none !important;
  }
  .stage.is-demo .ap__row {
    opacity: 1 !important;
    transform: none !important;
  }
  .stage.is-demo .ap__strike {
    transform: scaleX(1) !important;
  }
  .stage.is-demo .ap__save {
    transform: none !important;
  }
}
@media (max-width: 340px), (max-height: 220px) {
  .ap {
    width: min(268px, 92vw);
    padding: 8px;
  }
  .ap__ic svg {
    width: 16px;
    height: 16px;
  }
  .ap__plan {
    font-size: 11px;
  }
  .ap__sub {
    font-size: 9px;
  }
  .ap__toggle {
    margin-top: 8px;
    padding: 4px 8px;
    font-size: 10px;
  }
  .ap__stack {
    padding: 8px 0 0;
    gap: 4px;
  }
  .ap__label {
    font-size: 9px;
  }
  .ap__orig {
    font-size: 11px;
  }
  .ap__deal {
    font-size: 17px;
  }
  .ap__final {
    font-size: 12px;
  }
  .ap__save {
    padding: 0 8px;
    font-size: 9px;
  }
}

// 실제 동작: 토글 버튼을 누르면 패널이 grid 0fr→1fr 로 펼쳐지고 네 줄이 시차 등장한다.
// 처음 조작(pointerdown·keydown 1회)에서 측정용 루프 is-demo 를 뗀다.
var stage = document.querySelector('.stage');
var ap = document.querySelector('.ap');
var btn = document.querySelector('.ap__toggle');
['pointerdown', 'keydown'].forEach(function (t) {
  window.addEventListener(t, function () { stage.classList.remove('is-demo'); }, { once: true });
});
btn.addEventListener('click', function () {
  var open = ap.classList.toggle('is-open');
  btn.setAttribute('aria-expanded', String(open));
});

import { useEffect, useState } from "react";
import type { CSSProperties } from "react";
import styles from "./AnchorPriceStack.module.scss";

export type AnchorPriceStackProps = { duration?: number; easing?: string; color?: string };
type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string; "--i"?: string };

const ROWS = [
  { label: "정가", kind: "orig" },
  { label: "첫 달 할인가", kind: "deal" },
  { label: "쿠폰 적용가", kind: "final" },
  { label: "", kind: "save" },
];

export default function AnchorPriceStack({
  duration = 2000,
  easing = "cubic-bezier(.2,1.4,.4,1)",
  color = "#2f6df6",
}: AnchorPriceStackProps) {
  const [open, setOpen] = useState(false);
  // 측정용 루프: 처음 조작(pointerdown·keydown)에서 루프를 끈다 — vanilla 판과 같은 동작
  const [demo, setDemo] = useState(true);
  useEffect(() => {
    const off = () => setDemo(false);
    window.addEventListener("pointerdown", off, { once: true });
    window.addEventListener("keydown", off, { once: true });
    return () => {
      window.removeEventListener("pointerdown", off);
      window.removeEventListener("keydown", off);
    };
  }, []);

  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  const cls = [styles.ap, open ? styles.isOpen : "", demo ? styles.isDemo : ""].join(" ");

  return (
    <section className={cls} style={vars}>
      <header className={styles.head}>
        <span className={styles.ic} aria-hidden="true">
          <svg viewBox="0 0 256 256" width="20" height="20">
            <g fill="currentColor">
              <path d="M237.66 153L153 237.66a8 8 0 0 1-11.31 0l-99.35-99.32a8 8 0 0 1-2.34-5.65V40h92.69a8 8 0 0 1 5.65 2.34l99.32 99.32a8 8 0 0 1 0 11.34" opacity=".2" />
              <path d="M243.31 136L144 36.69A15.86 15.86 0 0 0 132.69 32H40a8 8 0 0 0-8 8v92.69A15.86 15.86 0 0 0 36.69 144L136 243.31a16 16 0 0 0 22.63 0l84.68-84.68a16 16 0 0 0 0-22.63m-96 96L48 132.69V48h84.69L232 147.31ZM96 84a12 12 0 1 1-12-12a12 12 0 0 1 12 12" />
            </g>
          </svg>
        </span>
        <div className={styles.tt}>
          <p className={styles.plan}>스타터 플랜</p>
          <p className={styles.sub}>첫 달 요금 알아보기</p>
        </div>
      </header>

      <button
        type="button"
        className={styles.toggle}
        aria-expanded={open}
        aria-controls="ap-panel"
        onClick={() => setOpen(!open)}
      >
        <span>가격 구성 보기</span>
        <svg className={styles.chev} viewBox="0 0 24 24" width="12" height="12" aria-hidden="true">
          <polyline points="6 9 12 15 18 9" fill="none" stroke="currentColor" strokeWidth={2.5} strokeLinecap="round" strokeLinejoin="round" />
        </svg>
      </button>

      <div className={styles.panel} id="ap-panel">
        <div className={styles.panelIn}>
          <ul className={styles.stack}>
            {ROWS.map((r, i) => {
              const rowVars: Vars = { "--i": String(i) };
              if (r.kind === "save") {
                return (
                  <li key={r.kind} className={`${styles.row} ${styles.rowSave}`} style={rowVars}>
                    <span className={styles.save}>₩38,700 절약</span>
                  </li>
                );
              }
              return (
                <li key={r.kind} className={styles.row} style={rowVars}>
                  <span className={styles.label}>{r.label}</span>
                  {r.kind === "orig" && (
                    <span className={styles.orig}>
                      ₩59,000
                      <span className={styles.strike} aria-hidden="true" />
                    </span>
                  )}
                  {r.kind === "deal" && <b className={styles.deal}>₩29,000</b>}
                  {r.kind === "final" && <span className={styles.final}>₩20,300</span>}
                </li>
              );
            })}
          </ul>
        </div>
      </div>
    </section>
  );
}