01Bong bóng bật hiện (pop-in)

<main class="stage">
  <div class="bubble is-demo">Vừa đến!</div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────────
$duration: $dur-quick;     // 실제 등장(팝)이 끝나는 데 걸리는 시간 — React 판 --duration 기본값
$easing: $ease-pop;        // 튀어나오듯 오버슈트 후 안착
$color: $subject-cream;    // 말풍선 색 (ink 무대라 cream)

@include stage($stage-ink);

.bubble {
  padding: 22px 34px;
  border-radius: $r-card;
  background: $color;
  color: $stage-ink;
  font-weight: 700; font-size: clamp(18px, 5.6vw, 24px); line-height: 1.4; font-family: inherit;
  transform-origin: center;

  &.is-demo {
    animation: bubble-pop-loop $dur-loop $easing infinite;
  }
}

// 한 주기(2s) 안에 팝 등장 → 유지 → 사라짐을 담아 gif 이음매가 안 보이게 한다
@keyframes bubble-pop-loop {
  0%   { transform: scale(.4); opacity: 0; }
  16%  { transform: scale(1.15); opacity: 1; }
  24%  { transform: scale(1); opacity: 1; }
  82%  { transform: scale(1); opacity: 1; }
  100% { transform: scale(.4); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .bubble.is-demo { animation: none !important; transform: none; opacity: 1; }
}

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);
}

.bubble {
  padding: 22px 34px;
  border-radius: 16px;
  background: #fff7e6;
  color: #17141a;
  font-weight: 700;
  font-size: clamp(18px, 5.6vw, 24px);
  line-height: 1.4;
  font-family: inherit;
  transform-origin: center;
}
.bubble.is-demo {
  animation: bubble-pop-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes bubble-pop-loop {
  0% {
    transform: scale(0.4);
    opacity: 0;
  }
  16% {
    transform: scale(1.15);
    opacity: 1;
  }
  24% {
    transform: scale(1);
    opacity: 1;
  }
  82% {
    transform: scale(1);
    opacity: 1;
  }
  100% {
    transform: scale(0.4);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .bubble.is-demo {
    animation: none !important;
    transform: none;
    opacity: 1;
  }
}

import type { CSSProperties, ReactNode } from "react";
import styles from "./BubblePopIn.module.scss";

export type BubblePopInProps = {
  children: ReactNode;
  /** 팝 등장이 끝나는 데 걸리는 시간 (기본 220ms) */
  duration?: number;
  /** easing (기본 오버슈트 포지션) */
  easing?: string;
  /** 말풍선 색 */
  color?: string;
  className?: string;
};

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

export default function BubblePopIn({
  children,
  duration = 220,
  easing = "cubic-bezier(.2, 1.4, .4, 1)",
  color = "#fff7e6",
  className = "",
}: BubblePopInProps) {
  const vars: Vars = {
    "--duration": `${duration}ms`,
    "--easing": easing,
    "--color": color,
  };

  return (
    <div className={`${styles.bubble} ${styles.enter} ${className}`} style={vars}>
      {children}
    </div>
  );
}