08Glassmorphism blur

<main class="stage stage--glass">
  <span class="bg-blob" aria-hidden="true"></span>
  <article class="card is-demo" tabindex="0">
    <div class="card__body">
      <h3 class="card__title">Premium widget</h3>
      <p class="card__meta">Live stats</p>
    </div>
  </article>
</main>

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

$duration: $dur-base;                                    // 블러·채도가 짙어지는 시간
$easing: $ease-out;
$color: $error;                                            // 배경 블롭 강조색

@include stage($stage-paper);
.stage { padding: clamp(8px, 2.4vw, 16px); position: relative; overflow: hidden; }

.bg-blob {
  position: absolute;
  inset: -20%;
  background:
    radial-gradient(circle at 30% 30%, $subject-blue, transparent 60%),
    radial-gradient(circle at 70% 70%, $color, transparent 60%);
}

.card {
  position: relative;
  z-index: 1;
  width: min(150px, 48vw);
  aspect-ratio: 4 / 3;
  border-radius: $r-card;
  padding: $sp-3;
  box-sizing: border-box;
  background: rgba(255, 255, 255, .14);
  border: 1px solid rgba(255, 255, 255, .3);
  backdrop-filter: blur(6px) saturate(120%);
  -webkit-backdrop-filter: blur(6px) saturate(120%);
  box-shadow: $shadow-press;
  outline: none;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  justify-content: center;
  transform: translateY(0);
  transition: backdrop-filter $duration $easing, background $duration $easing, box-shadow $duration $easing, transform $duration $easing;
}
.card__title { margin: 0 0 $sp-1; font-weight: 700; font-size: clamp(12px, 3.4vw, 14px); line-height: 1.3; font-family: inherit; color: $stage-ink; }
.card__meta { margin: 0; font-weight: 500; font-size: clamp(11px, 3vw, 12px); line-height: 1.3; font-family: inherit; color: rgba($stage-ink, .85); }

.card:hover,
.card:focus-visible,
.card:active {
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  background: rgba(255, 255, 255, .26);
  box-shadow: $shadow-raised;
  transform: translateY(-4px);
}
.card.is-demo { animation: glass-loop $dur-loop $easing infinite; }
@keyframes glass-loop {
  0%, 15% {
    backdrop-filter: blur(6px) saturate(120%);
    background: rgba(255, 255, 255, .14);
    box-shadow: $shadow-press;
    transform: translateY(0);
  }
  45%, 75% {
    backdrop-filter: blur(14px) saturate(160%);
    background: rgba(255, 255, 255, .26);
    box-shadow: $shadow-raised;
    transform: translateY(-4px);
  }
  100% {
    backdrop-filter: blur(6px) saturate(120%);
    background: rgba(255, 255, 255, .14);
    box-shadow: $shadow-press;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  .card { transition: none; }
  .card.is-demo { animation: none; backdrop-filter: blur(14px) saturate(160%); background: rgba(255, 255, 255, .26); transform: none; }
}

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);
}

.stage {
  padding: clamp(8px, 2.4vw, 16px);
  position: relative;
  overflow: hidden;
}

.bg-blob {
  position: absolute;
  inset: -20%;
  background: radial-gradient(circle at 30% 30%, #2f6df6, transparent 60%), radial-gradient(circle at 70% 70%, #c2361a, transparent 60%);
}

.card {
  position: relative;
  z-index: 1;
  width: min(150px, 48vw);
  aspect-ratio: 4/3;
  border-radius: 16px;
  padding: 12px;
  box-sizing: border-box;
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(6px) saturate(120%);
  -webkit-backdrop-filter: blur(6px) saturate(120%);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  outline: none;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  justify-content: center;
  transform: translateY(0);
  transition: backdrop-filter 300ms ease-out, background 300ms ease-out, box-shadow 300ms ease-out, transform 300ms ease-out;
}

.card__title {
  margin: 0 0 4px;
  font-weight: 700;
  font-size: clamp(12px, 3.4vw, 14px);
  line-height: 1.3;
  font-family: inherit;
  color: #17141a;
}

.card__meta {
  margin: 0;
  font-weight: 500;
  font-size: clamp(11px, 3vw, 12px);
  line-height: 1.3;
  font-family: inherit;
  color: rgba(23, 20, 26, 0.85);
}

.card:hover,
.card:focus-visible,
.card:active {
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  background: rgba(255, 255, 255, 0.26);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform: translateY(-4px);
}

.card.is-demo {
  animation: glass-loop 2s ease-out infinite;
}

@keyframes glass-loop {
  0%, 15% {
    backdrop-filter: blur(6px) saturate(120%);
    background: rgba(255, 255, 255, 0.14);
    box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
    transform: translateY(0);
  }
  45%, 75% {
    backdrop-filter: blur(14px) saturate(160%);
    background: rgba(255, 255, 255, 0.26);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
    transform: translateY(-4px);
  }
  100% {
    backdrop-filter: blur(6px) saturate(120%);
    background: rgba(255, 255, 255, 0.14);
    box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
    transform: translateY(0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .card {
    transition: none;
  }
  .card.is-demo {
    animation: none;
    backdrop-filter: blur(14px) saturate(160%);
    background: rgba(255, 255, 255, 0.26);
    transform: none;
  }
}

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

export type GlassCardProps = {
  title: string;
  meta: string;
  /** 블러·채도가 짙어지는 시간 (기본 300ms) */
  duration?: number;
  easing?: string;
  /** 배경 블롭 강조색 */
  color?: string;
};

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

export default function GlassCard({
  title,
  meta,
  duration = 300,
  easing = "ease-out",
  color = "#c2361a",
}: GlassCardProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  return (
    <div className={styles.stage} style={vars}>
      <span className={styles.blob} aria-hidden="true" />
      <article className={styles.card} tabIndex={0}>
        <h3 className={styles.title}>{title}</h3>
        <p className={styles.meta}>{meta}</p>
      </article>
    </div>
  );
}