02ビフォーアフター

<main class="stage">
  <section class="ba">
    <div class="ba__toggle" role="group" aria-label="比較を見る">
      <button type="button" class="ba__btn" data-panel="before" aria-pressed="true">Before</button>
      <button type="button" class="ba__btn" data-panel="after" aria-pressed="false">After</button>
    </div>
    <div class="ba__frame">
      <div class="ba__panel ba__panel--before" data-panel="before">
        <span class="ba__badge">前</span>
        <span class="ba__shape"></span>
      </div>
      <div class="ba__panel ba__panel--after" data-panel="after">
        <span class="ba__badge ba__badge--after">後</span>
        <span class="ba__shape ba__shape--after"></span>
      </div>
      <span class="ba__shimmer" aria-hidden="true"></span>
    </div>
  </section>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-enter;                                // 패널 크로스페이드
$easing: $ease-spring;
$color: $subject-blue;

@include stage($stage-yellow);

.ba { width: min(400px, 96vw); display: flex; flex-direction: column; gap: $sp-3; }

.ba__toggle { display: flex; gap: $sp-2; }
.ba__btn {
  border: 0;
  cursor: pointer;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(23, 20, 26, .08);
  color: $subject-ink;
  font-weight: 700; font-size: 11px; line-height: 1; font-family: inherit;
  transition: background $dur-quick $ease-out, color $dur-quick $ease-out;
}
.ba__btn[aria-pressed="true"] { background: $subject-ink; color: $subject-cream; }

.ba__frame {
  position: relative;
  width: 100%;
  height: 150px;
  border-radius: $r-card;
  overflow: hidden;
  isolation: isolate;
}
.ba__panel {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: $sp-3;
  box-sizing: border-box;
  opacity: 0;
  transition: opacity $duration $easing;
}
.ba__panel.is-active { opacity: 1; }
.ba__panel--before { background: rgba(23, 20, 26, .82); opacity: 1; } // 기본 활성
.ba__panel--after { background: linear-gradient(160deg, $subject-ink, #24304f); }

.ba__badge {
  position: absolute;
  top: $sp-2;
  left: $sp-2;
  padding: $sp-1 $sp-2;
  border-radius: $r-xs;
  background: rgba(255, 247, 230, .16);
  color: $subject-cream;
  font-weight: 700; font-size: 9px; line-height: 1; font-family: inherit;
  letter-spacing: .06em;
}
.ba__badge--after { background: rgba(47, 109, 246, .3); }

.ba__shape {
  width: 64%;
  height: 64px;
  border-radius: $r-sm;
  background: rgba(255, 247, 230, .18);
}
.ba__shape--after { background: rgba(47, 109, 246, .5); box-shadow: $shadow-raised; }

// 무대 장식: 어느 패널이 켜져 있든 항상 보이도록 프레임 위(두 패널의 형제, z-index 위)에 둔다 —
// 처음엔 .ba__panel--after 안에 넣었더니 그 패널이 opacity:0(기본은 before 활성)이라 함께 숨어 측정값이 0 이었다.
.ba__shimmer {
  position: absolute;
  inset: -20% -60%;
  z-index: 2;
  pointer-events: none;
  background: linear-gradient(100deg, transparent 42%, rgba(255, 247, 230, .42) 50%, transparent 58%);
  animation: ba-shimmer 2.4s linear infinite;
}
@keyframes ba-shimmer {
  0%   { transform: translateX(-30%); opacity: 0; }
  10%  { opacity: .9; }
  60%  { opacity: .9; }
  100% { transform: translateX(30%); opacity: 0; }
}

// ── 접근성 ──────────────────────────────────────────
@media (prefers-reduced-motion: reduce) {
  .ba__shimmer { animation: none !important; opacity: 0 !important; }
  .ba__panel, .ba__btn { transition: none !important; }
}

// ── 반응형(320×200) ──────────────────────────────────
@media (max-width: 340px), (max-height: 220px) {
  .ba__frame { height: 108px; }
  .ba__shape { height: 44px; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.ba {
  width: min(400px, 96vw);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.ba__toggle {
  display: flex;
  gap: 8px;
}

.ba__btn {
  border: 0;
  cursor: pointer;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.08);
  color: #17141a;
  font-weight: 700;
  font-size: 11px;
  line-height: 1;
  font-family: inherit;
  transition: background 220ms ease-out, color 220ms ease-out;
}

.ba__btn[aria-pressed=true] {
  background: #17141a;
  color: #fff7e6;
}

.ba__frame {
  position: relative;
  width: 100%;
  height: 150px;
  border-radius: 16px;
  overflow: hidden;
  isolation: isolate;
}

.ba__panel {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 12px;
  box-sizing: border-box;
  opacity: 0;
  transition: opacity 600ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.ba__panel.is-active {
  opacity: 1;
}

.ba__panel--before {
  background: rgba(23, 20, 26, 0.82);
  opacity: 1;
}

.ba__panel--after {
  background: linear-gradient(160deg, #17141a, #24304f);
}

.ba__badge {
  position: absolute;
  top: 8px;
  left: 8px;
  padding: 4px 8px;
  border-radius: 4px;
  background: rgba(255, 247, 230, 0.16);
  color: #fff7e6;
  font-weight: 700;
  font-size: 9px;
  line-height: 1;
  font-family: inherit;
  letter-spacing: 0.06em;
}

.ba__badge--after {
  background: rgba(47, 109, 246, 0.3);
}

.ba__shape {
  width: 64%;
  height: 64px;
  border-radius: 8px;
  background: rgba(255, 247, 230, 0.18);
}

.ba__shape--after {
  background: rgba(47, 109, 246, 0.5);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.ba__shimmer {
  position: absolute;
  inset: -20% -60%;
  z-index: 2;
  pointer-events: none;
  background: linear-gradient(100deg, transparent 42%, rgba(255, 247, 230, 0.42) 50%, transparent 58%);
  animation: ba-shimmer 2.4s linear infinite;
}

@keyframes ba-shimmer {
  0% {
    transform: translateX(-30%);
    opacity: 0;
  }
  10% {
    opacity: 0.9;
  }
  60% {
    opacity: 0.9;
  }
  100% {
    transform: translateX(30%);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ba__shimmer {
    animation: none !important;
    opacity: 0 !important;
  }
  .ba__panel, .ba__btn {
    transition: none !important;
  }
}
@media (max-width: 340px), (max-height: 220px) {
  .ba__frame {
    height: 108px;
  }
  .ba__shape {
    height: 44px;
  }
}

// 실제 동작: 버튼 클릭 時 두 패널 중 하나만 opacity:1 로 크로스페이드, aria-pressed 가 배타적으로 갱신된다.
var btns = document.querySelectorAll('.ba__btn');
var panels = document.querySelectorAll('.ba__panel');
btns.forEach(function (btn) {
  btn.addEventListener('click', function () {
    var name = btn.getAttribute('data-panel');
    btns.forEach(function (b) { b.setAttribute('aria-pressed', String(b === btn)); });
    panels.forEach(function (p) { p.classList.toggle('is-active', p.getAttribute('data-panel') === name); });
  });
});

import { useState } from "react";
import type { CSSProperties } from "react";
import styles from "./BeforeAfter.module.scss";

export type BeforeAfterProps = { duration?: number; easing?: string; color?: string };
type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type Panel = "before" | "after";

export default function BeforeAfter({ duration = 600, easing = "cubic-bezier(.2,.8,.2,1)", color = "#2f6df6" }: BeforeAfterProps) {
  const [active, setActive] = useState<Panel>("before");
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <section className={styles.ba} style={vars}>
      <div className={styles.toggle} role="group" aria-label="비교 보기">
        <button type="button" className={styles.btn} aria-pressed={active === "before"} onClick={() => setActive("before")}>Before</button>
        <button type="button" className={styles.btn} aria-pressed={active === "after"} onClick={() => setActive("after")}>After</button>
      </div>
      <div className={styles.frame}>
        <div className={`${styles.panel} ${styles.before} ${active === "before" ? styles.active : ""}`}>
          <span className={styles.badge}>이전</span>
          <span className={styles.shape} />
        </div>
        <div className={`${styles.panel} ${styles.after} ${active === "after" ? styles.active : ""}`}>
          <span className={`${styles.badge} ${styles.badgeAfter}`}>이후</span>
          <span className={`${styles.shape} ${styles.shapeAfter}`} />
        </div>
        <span className={styles.shimmer} aria-hidden="true" />
      </div>
    </section>
  );
}