07ないキーがそのまま画面に出る

<main class="stage is-demo">
  <div class="win">
    <header class="win__bar"><span class="win__dot"></span><span class="win__dot"></span><span class="win__dot"></span></header>
    <div class="win__body">
      <div class="slot">
        <p class="slot__raw">welcome.title</p>
        <p class="slot__fb">おかえりなさい</p>
      </div>
      <span class="win__chip">フォールバック表示</span>
    </div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;      // 2s — 키 노출 ↔ 폴백 한 주기
$easing: $ease-out;
$color: $subject-cream;    // 창 카드

@include stage($stage-orange);

.win {
  width: min(330px, 92vw);
  border-radius: $r-card;
  background: $color;
  box-shadow: $shadow-raised;
  overflow: hidden;
}

.win__bar {
  display: flex;
  column-gap: $sp-1;
  padding: $sp-2 $sp-3 0;
}

.win__dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: rgba($subject-ink, .18);
}

.win__body {
  position: relative;
  padding: $sp-3 $sp-4 $sp-5;
  min-height: clamp(96px, 32vw, 150px);
  display: grid;
  place-items: center;
}

.slot {
  position: relative;
  width: 100%;
  min-height: 64px;
}

.slot__raw, .slot__fb {
  position: absolute;
  inset: 0;
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.slot__raw {
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: clamp(13px, 3.4vw, 20px);
  font-weight: 700;
  color: $error;
  border: 2px dashed rgba($error, .5);
  border-radius: $r-control;
}

.slot__fb {
  font-size: clamp(14px, 3.8vw, 22px);
  font-weight: 800;
  color: $subject-ink;
  background: rgba($subject-blue, .14);
  border-radius: $r-control;
  transform: translateY(14px) scale(.94);
  opacity: 0;
}

.win__chip {
  position: absolute;
  right: $sp-2;
  bottom: $sp-2;
  border-radius: $r-pill;
  background: $subject-blue;
  color: #fff;
  font-size: clamp(9px, 2.2vw, 12px);
  font-weight: 800;
  padding: $sp-1 $sp-2;
  opacity: 0;
}

// 원시 키가 빠지고, 그 자리에 폴백 문구가 뜬다 — 순서대로만 (겹침 없음)
.stage.is-demo .slot__raw { animation: raw-out $duration $easing infinite; }
.stage.is-demo .slot__fb { animation: fb-in $duration $ease-pop infinite; }
.stage.is-demo .win__chip { animation: chip-in $duration $ease-pop infinite; }

@keyframes raw-out {
  0%, 20%  { transform: translateY(0) scale(1); opacity: 1; }
  28%      { transform: translateY(-16px) scale(.94); opacity: 0; }
  88%      { transform: translateY(-16px) scale(.94); opacity: 0; }
  96%, 100%{ transform: translateY(0) scale(1); opacity: 1; }
}
@keyframes fb-in {
  0%, 30%  { transform: translateY(14px) scale(.9); opacity: 0; }
  42%      { transform: translateY(0) scale(1.04); opacity: 1; }
  48%, 80% { transform: translateY(0) scale(1); opacity: 1; }
  88%, 100%{ transform: translateY(14px) scale(.9); opacity: 0; }
}
@keyframes chip-in {
  0%, 38%  { transform: scale(0); opacity: 0; }
  48%      { transform: scale(1.18); opacity: 1; }
  54%, 78% { transform: scale(1); opacity: 1; }
  86%, 100%{ transform: scale(.4); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .slot__raw,
  .stage.is-demo .slot__fb,
  .stage.is-demo .win__chip { animation: none; }
  .slot__raw { transform: translateY(-16px); opacity: 0; }
  .slot__fb { transform: translateY(0) scale(1); opacity: 1; }
  .win__chip { opacity: 1; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.win {
  width: min(330px, 92vw);
  border-radius: 16px;
  background: #fff7e6;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  overflow: hidden;
}

.win__bar {
  display: flex;
  column-gap: 4px;
  padding: 8px 12px 0;
}

.win__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(23, 20, 26, 0.18);
}

.win__body {
  position: relative;
  padding: 12px 16px 20px;
  min-height: clamp(96px, 32vw, 150px);
  display: grid;
  place-items: center;
}

.slot {
  position: relative;
  width: 100%;
  min-height: 64px;
}

.slot__raw, .slot__fb {
  position: absolute;
  inset: 0;
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.slot__raw {
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: clamp(13px, 3.4vw, 20px);
  font-weight: 700;
  color: #c2361a;
  border: 2px dashed rgba(194, 54, 26, 0.5);
  border-radius: 12px;
}

.slot__fb {
  font-size: clamp(14px, 3.8vw, 22px);
  font-weight: 800;
  color: #17141a;
  background: rgba(47, 109, 246, 0.14);
  border-radius: 12px;
  transform: translateY(14px) scale(0.94);
  opacity: 0;
}

.win__chip {
  position: absolute;
  right: 8px;
  bottom: 8px;
  border-radius: 999px;
  background: #2f6df6;
  color: #fff;
  font-size: clamp(9px, 2.2vw, 12px);
  font-weight: 800;
  padding: 4px 8px;
  opacity: 0;
}

.stage.is-demo .slot__raw {
  animation: raw-out 2s ease-out infinite;
}

.stage.is-demo .slot__fb {
  animation: fb-in 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.stage.is-demo .win__chip {
  animation: chip-in 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes raw-out {
  0%, 20% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
  28% {
    transform: translateY(-16px) scale(0.94);
    opacity: 0;
  }
  88% {
    transform: translateY(-16px) scale(0.94);
    opacity: 0;
  }
  96%, 100% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
}
@keyframes fb-in {
  0%, 30% {
    transform: translateY(14px) scale(0.9);
    opacity: 0;
  }
  42% {
    transform: translateY(0) scale(1.04);
    opacity: 1;
  }
  48%, 80% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
  88%, 100% {
    transform: translateY(14px) scale(0.9);
    opacity: 0;
  }
}
@keyframes chip-in {
  0%, 38% {
    transform: scale(0);
    opacity: 0;
  }
  48% {
    transform: scale(1.18);
    opacity: 1;
  }
  54%, 78% {
    transform: scale(1);
    opacity: 1;
  }
  86%, 100% {
    transform: scale(0.4);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .slot__raw,
  .stage.is-demo .slot__fb,
  .stage.is-demo .win__chip {
    animation: none;
  }
  .slot__raw {
    transform: translateY(-16px);
    opacity: 0;
  }
  .slot__fb {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
  .win__chip {
    opacity: 1;
  }
}

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

export type FallbackKeySwapProps = {
  duration?: number;
  easing?: string;
  color?: string;
  rawKey?: string;
  fallback?: string;
  chip?: string;
};

export default function FallbackKeySwap({
  duration = 2000,
  easing = "cubic-bezier(.2, 1.4, .4, 1)",
  color = "#fff7e6",
  rawKey = "welcome.title",
  fallback = "다시 오신 걸 환영합니다",
  chip = "폴백 적용",
}: FallbackKeySwapProps) {
  const vars: CSSProperties = { "--duration": `${duration}ms`, "--easing": easing, "--color": color } as CSSProperties;
  return (
    <div className={styles.stage} style={vars} aria-label="폴백 처리 데모" role="img">
      <div className={styles.win}>
        <header className={styles.bar}>
          <span className={styles.dot} />
          <span className={styles.dot} />
          <span className={styles.dot} />
        </header>
        <div className={styles.body}>
          <div className={styles.slot}>
            <p className={styles.raw}>{rawKey}</p>
            <p className={styles.fb}>{fallback}</p>
          </div>
          <span className={styles.chip}>{chip}</span>
        </div>
      </div>
    </div>
  );
}