03Viền glow đập nhịp

<main class="stage is-demo">
  <div class="card">
    <span class="dot" aria-hidden="true"></span>
    <span class="bar bar--lg" aria-hidden="true"></span>
    <span class="bar bar--sm" aria-hidden="true"></span>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;   // 2s — 펄스 한 주기
$easing: ease-in-out;
$color: #39ff88;        // 네온 그린 (라이브 상태)

@include stage($stage-ink);

.card {
  position: relative;
  box-sizing: border-box;
  width: clamp(180px, 56vmin, 260px);
  padding: $sp-6 $sp-5;
  border-radius: $r-card;
  border: 1px solid rgba($color, .5);
  background: rgba($stage-paper, .04);
  display: flex; flex-direction: column; gap: $sp-3;
}

.dot {
  width: $sp-2; height: $sp-2; border-radius: 50%;
  background: $color;
  box-shadow: 0 0 $sp-2 $color;
}

.bar { display: block; height: $sp-2; border-radius: $r-xs; background: rgba($stage-paper, .18); }
.bar--lg { width: 70%; }
.bar--sm { width: 45%; }

// box-shadow 스프레드·불투명도만 바뀐다 — 테두리 위치·카드 크기는 고정
.stage.is-demo .card {
  animation: pulse $duration $easing infinite;
}

@keyframes pulse {
  0%, 100% {
    box-shadow: 0 0 0 rgba($color, 0), 0 0 $sp-2 rgba($color, .18);
    border-color: rgba($color, .35);
  }
  50% {
    box-shadow: 0 0 $sp-1 rgba($color, .7), 0 0 $sp-8 rgba($color, .55), 0 0 $sp-12 rgba($color, .22);
    border-color: rgba($color, .9);
  }
}

@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .card { animation: none; box-shadow: 0 0 $sp-2 rgba($color, .4); }
}

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);
}

.card {
  position: relative;
  box-sizing: border-box;
  width: clamp(180px, 56vmin, 260px);
  padding: 24px 20px;
  border-radius: 16px;
  border: 1px solid rgba(57, 255, 136, 0.5);
  background: rgba(255, 255, 255, 0.04);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #39ff88;
  box-shadow: 0 0 8px #39ff88;
}

.bar {
  display: block;
  height: 8px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.18);
}

.bar--lg {
  width: 70%;
}

.bar--sm {
  width: 45%;
}

.stage.is-demo .card {
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% {
    box-shadow: 0 0 0 rgba(57, 255, 136, 0), 0 0 8px rgba(57, 255, 136, 0.18);
    border-color: rgba(57, 255, 136, 0.35);
  }
  50% {
    box-shadow: 0 0 4px rgba(57, 255, 136, 0.7), 0 0 32px rgba(57, 255, 136, 0.55), 0 0 48px rgba(57, 255, 136, 0.22);
    border-color: rgba(57, 255, 136, 0.9);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .card {
    animation: none;
    box-shadow: 0 0 8px rgba(57, 255, 136, 0.4);
  }
}

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

export type BorderGlowPulseProps = {
  /** 펄스 한 주기 (기본 2000ms) */
  duration?: number;
  color?: string;
  /** 카드 안에 넣을 내용. 기본은 뼈대(스켈레톤) 두 줄 */
  children?: ReactNode;
};

export default function BorderGlowPulse({
  duration = 2000,
  color = "#39ff88",
  children,
}: BorderGlowPulseProps) {
  const vars: CSSProperties = { "--duration": `${duration}ms`, "--color": color } as CSSProperties;
  return (
    <div className={styles.card} style={vars}>
      <span className={styles.dot} aria-hidden="true" />
      {children ?? (
        <>
          <span className={`${styles.bar} ${styles.barLg}`} />
          <span className={`${styles.bar} ${styles.barSm}`} />
        </>
      )}
    </div>
  );
}