08Glass toggle

<main class="stage">
  <label class="sw is-demo">
    <input type="checkbox" class="sw__input">
    <span class="sw__track"><span class="sw__knob"></span></span>
    <span class="sw__label">Notifications</span>
  </label>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-base;
$easing: $ease-spring;
$color: $subject-blue;

@include stage($stage-paper);

.sw {
  display: inline-flex;
  align-items: center;
  gap: $sp-3;
  cursor: pointer;
}
.sw__input { position: absolute; opacity: 0; pointer-events: none; }

// 무대(paper, 흰색) 위에서 흰 유리 트랙은 대비가 거의 사라졌다 (실측: poster.png 가 거의 빈 화면으로 보임) —
// 트랙 색조를 잉크 쪽으로 옮기고 테두리·그림자를 짙게 해 흰 무대에서도 윤곽이 읽히게 했다
.sw__track {
  position: relative;
  flex: 0 0 auto;
  width: 52px;
  height: 30px;
  box-sizing: border-box;
  border-radius: $r-pill;
  background: rgba($subject-ink, .1);
  border: 1px solid rgba($subject-ink, .22);
  backdrop-filter: blur(10px) saturate(160%);
  -webkit-backdrop-filter: blur(10px) saturate(160%);
  box-shadow: 0 2px 6px rgba($subject-ink, .18);
}
.sw__knob {
  position: absolute;
  top: 2px; left: 2px;
  width: 24px; height: 24px;
  border-radius: 50%;
  background: rgba(255, 255, 255, .96);
  border: 1px solid rgba($subject-ink, .14);
  box-shadow: $shadow-press;
  transform: translateX(0);
  transition: transform $duration $easing, box-shadow $duration $easing;
}
.sw__label { color: $subject-ink; font: 600 12px/1 -apple-system, "Segoe UI", sans-serif; }

// 실사용: 체크박스 상태만으로 손잡이가 이동한다
.sw__input:checked ~ .sw__track .sw__knob {
  transform: translateX(22px);
  box-shadow: $shadow-raised;
}
.sw__input:checked ~ .sw__track { background: rgba($color, .55); }

// 데모 루프: 클릭 전까지 켜짐·꺼짐을 스스로 오간다
@keyframes sw-knob-loop {
  0%, 20%  { transform: translateX(0); box-shadow: $shadow-press; }
  50%, 70% { transform: translateX(22px); box-shadow: $shadow-raised; }
  100%     { transform: translateX(0); box-shadow: $shadow-press; }
}
.sw.is-demo .sw__knob { animation: sw-knob-loop $dur-loop $easing infinite; }

@media (prefers-reduced-motion: reduce) {
  .sw__knob { transition: none; }
  .sw.is-demo .sw__knob { animation: none !important; }
}

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);
}

.sw {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
}

.sw__input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.sw__track {
  position: relative;
  flex: 0 0 auto;
  width: 52px;
  height: 30px;
  box-sizing: border-box;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.1);
  border: 1px solid rgba(23, 20, 26, 0.22);
  backdrop-filter: blur(10px) saturate(160%);
  -webkit-backdrop-filter: blur(10px) saturate(160%);
  box-shadow: 0 2px 6px rgba(23, 20, 26, 0.18);
}

.sw__knob {
  position: absolute;
  top: 2px;
  left: 2px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.96);
  border: 1px solid rgba(23, 20, 26, 0.14);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  transform: translateX(0);
  transition: transform 300ms cubic-bezier(0.2, 0.8, 0.2, 1), box-shadow 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.sw__label {
  color: #17141a;
  font: 600 12px/1 -apple-system, "Segoe UI", sans-serif;
}

.sw__input:checked ~ .sw__track .sw__knob {
  transform: translateX(22px);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.sw__input:checked ~ .sw__track {
  background: rgba(47, 109, 246, 0.55);
}

@keyframes sw-knob-loop {
  0%, 20% {
    transform: translateX(0);
    box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  }
  50%, 70% {
    transform: translateX(22px);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  100% {
    transform: translateX(0);
    box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  }
}
.sw.is-demo .sw__knob {
  animation: sw-knob-loop 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@media (prefers-reduced-motion: reduce) {
  .sw__knob {
    transition: none;
  }
  .sw.is-demo .sw__knob {
    animation: none !important;
  }
}

// 체크박스가 진짜 켜짐·꺼짐을 낸다. 실제로 누르면 데모 루프(.is-demo)만 뗀다.
document.querySelector('.sw__input').addEventListener('pointerdown', function () {
  document.querySelector('.sw').classList.remove('is-demo');
});

import { CSSProperties, useState } from "react";
import styles from "./GlassToggle.module.scss";

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

export interface GlassToggleProps {
  duration?: string;
  easing?: string;
  color?: string;
}

export default function GlassToggle({
  duration = "300ms",
  easing = "cubic-bezier(.2, .8, .2, 1)",
  color = "#2f6df6",
}: GlassToggleProps) {
  const [on, setOn] = useState(false);
  const style: Vars = { "--duration": duration, "--easing": easing, "--color": color };

  return (
    <button
      type="button"
      className={styles.sw}
      style={style}
      role="switch"
      aria-checked={on}
      onClick={() => setOn((v) => !v)}
    >
      <span className={`${styles.track} ${on ? styles.on : ""}`}>
        <span className={`${styles.knob} ${on ? styles.on : ""}`} />
      </span>
      <span className={styles.label}>Notifications</span>
    </button>
  );
}