01Glassmorphic login card

<main class="stage">
  <div class="glass-scene is-demo">
    <span class="glass-scene__blob glass-scene__blob--a" aria-hidden="true"></span>
    <span class="glass-scene__blob glass-scene__blob--b" aria-hidden="true"></span>
    <form class="glass-card" autocomplete="off">
      <h2 class="glass-card__title">Welcome back</h2>
      <input class="glass-card__input" type="email" placeholder="Email">
      <input class="glass-card__input" type="password" placeholder="Password">
      <button class="glass-card__btn" type="button">Log in</button>
    </form>
  </div>
</main>

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

$duration: $dur-base;                                  // 카드 진입·호버 전환 시간
$easing: $ease-out;
$color: $subject-blue;                                 // 블롭 색 1

@include stage($stage-ink);

.glass-scene {
  position: relative;
  width: min(240px, 80vw);
  height: 168px;
  display: grid;
  place-items: center;
  overflow: hidden;
  border-radius: $r-card;
}
.glass-scene__blob {
  position: absolute;
  width: 140px;
  height: 140px;
  border-radius: 50%;
  filter: blur(2px);
  opacity: 1;
  transform: translate(-30px, -20px);
}
.glass-scene__blob--a { background: radial-gradient(circle, #c5dfe2, transparent 68%); top: 8%; left: 8%; }
.glass-scene__blob--b { background: radial-gradient(circle, #eddae1, transparent 68%); bottom: 3%; right: 3%; }

.glass-card {
  position: relative;
  z-index: 1;
  width: min(185px, 66vw);
  padding: $sp-3;
  display: flex;
  flex-direction: column;
  gap: $sp-1;
  background: rgba(255, 255, 255, .14);
  border: 1px solid rgba(255, 255, 255, .35);
  border-radius: $r-card;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: $shadow-raised;
}
.glass-card__title { margin: 0 0 $sp-1; color: $stage-paper; font-size: 15px; font-weight: 700; font-family: inherit; }
.glass-card__input {
  width: 100%;
  box-sizing: border-box;
  padding: $sp-2 $sp-3;
  border-radius: $r-sm;
  border: 1px solid rgba(255, 255, 255, .3);
  background: rgba(255, 255, 255, .12);
  color: $stage-paper;
  font-size: 12px;
  font-family: inherit;
  &::placeholder { color: rgba(255, 255, 255, .65); }
  &:focus-visible { outline: 2px solid $stage-paper; outline-offset: 1px; }
}
.glass-card__btn {
  margin-top: $sp-1;
  padding: $sp-2;
  border: none;
  border-radius: $r-sm;
  background: $color;
  color: $stage-paper;
  font-weight: 700;
  font-size: 12px;
  font-family: inherit;
  cursor: pointer;
  transition: transform $dur-instant $easing, box-shadow $dur-instant $easing;
  &:hover, &:focus-visible { transform: translateY(-1px); box-shadow: $shadow-press; }
  &:active { transform: translateY(0); }
}

.glass-scene.is-demo .glass-scene__blob--a { animation: drift-a $dur-loop $easing infinite; }
.glass-scene.is-demo .glass-scene__blob--b { animation: drift-b $dur-loop $easing infinite; }

@keyframes drift-a {
  0%, 100% { transform: translate(-30px, -20px) scale(1); }
  50%      { transform: translate(40px, 30px) scale(1.15); }
}
@keyframes drift-b {
  0%, 100% { transform: translate(20px, 10px) scale(1); }
  50%      { transform: translate(-40px, -25px) scale(1.2); }
}

@media (prefers-reduced-motion: reduce) {
  .glass-scene.is-demo .glass-scene__blob--a,
  .glass-scene.is-demo .glass-scene__blob--b { animation: none; }
  .glass-card__btn { transition: none; }
}

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);
}

.glass-scene {
  position: relative;
  width: min(240px, 80vw);
  height: 168px;
  display: grid;
  place-items: center;
  overflow: hidden;
  border-radius: 16px;
}

.glass-scene__blob {
  position: absolute;
  width: 140px;
  height: 140px;
  border-radius: 50%;
  filter: blur(2px);
  opacity: 1;
  transform: translate(-30px, -20px);
}

.glass-scene__blob--a {
  background: radial-gradient(circle, #c5dfe2, transparent 68%);
  top: 8%;
  left: 8%;
}

.glass-scene__blob--b {
  background: radial-gradient(circle, #eddae1, transparent 68%);
  bottom: 3%;
  right: 3%;
}

.glass-card {
  position: relative;
  z-index: 1;
  width: min(185px, 66vw);
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 16px;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.glass-card__title {
  margin: 0 0 4px;
  color: #ffffff;
  font-size: 15px;
  font-weight: 700;
  font-family: inherit;
}

.glass-card__input {
  width: 100%;
  box-sizing: border-box;
  padding: 8px 12px;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
  font-size: 12px;
  font-family: inherit;
}
.glass-card__input::placeholder {
  color: rgba(255, 255, 255, 0.65);
}
.glass-card__input:focus-visible {
  outline: 2px solid #ffffff;
  outline-offset: 1px;
}

.glass-card__btn {
  margin-top: 4px;
  padding: 8px;
  border: none;
  border-radius: 8px;
  background: #2f6df6;
  color: #ffffff;
  font-weight: 700;
  font-size: 12px;
  font-family: inherit;
  cursor: pointer;
  transition: transform 140ms ease-out, box-shadow 140ms ease-out;
}
.glass-card__btn:hover, .glass-card__btn:focus-visible {
  transform: translateY(-1px);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}
.glass-card__btn:active {
  transform: translateY(0);
}

.glass-scene.is-demo .glass-scene__blob--a {
  animation: drift-a 2s ease-out infinite;
}

.glass-scene.is-demo .glass-scene__blob--b {
  animation: drift-b 2s ease-out infinite;
}

@keyframes drift-a {
  0%, 100% {
    transform: translate(-30px, -20px) scale(1);
  }
  50% {
    transform: translate(40px, 30px) scale(1.15);
  }
}
@keyframes drift-b {
  0%, 100% {
    transform: translate(20px, 10px) scale(1);
  }
  50% {
    transform: translate(-40px, -25px) scale(1.2);
  }
}
@media (prefers-reduced-motion: reduce) {
  .glass-scene.is-demo .glass-scene__blob--a,
  .glass-scene.is-demo .glass-scene__blob--b {
    animation: none;
  }
  .glass-card__btn {
    transition: none;
  }
}

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

export type GlassLoginCardProps = {
  /** 카드 등장 전환 시간 (기본 300ms) */
  duration?: number;
  easing?: string;
  /** 카드 뒤 블롭 색 1 */
  color?: string;
};

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

/** 반투명 카드가 backdrop-filter 로 뒤 블롭을 흐리게 비춘다. 블롭은 항상 천천히 움직인다 */
export default function GlassLoginCard({
  duration = 300,
  easing = "ease-out",
  color = "#2f6df6",
}: GlassLoginCardProps) {
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };
  return (
    <div className={styles.scene} style={vars}>
      <span className={`${styles.blob} ${styles.blobA}`} aria-hidden="true" />
      <span className={`${styles.blob} ${styles.blobB}`} aria-hidden="true" />
      <form className={styles.card} onSubmit={(e: { preventDefault(): void }) => e.preventDefault()}>
        <h2 className={styles.title}>Welcome back</h2>
        <input className={styles.input} type="email" placeholder="Email" />
        <input className={styles.input} type="password" placeholder="Password" />
        <button className={styles.btn} type="submit">Log in</button>
      </form>
    </div>
  );
}