08Size variant mixin

<main class="stage">
  <p class="group__title">Auto sync</p>
  <div class="group">
    <label class="switch switch--sm is-demo">
      <input type="checkbox" class="switch__input" role="switch" aria-label="Small">
      <span class="switch__track">
        <span class="switch__bg switch__bg--off"></span>
        <span class="switch__bg switch__bg--on"></span>
        <span class="switch__knob"></span>
      </span>
    </label>
    <label class="switch switch--md is-demo">
      <input type="checkbox" class="switch__input" role="switch" aria-label="Medium">
      <span class="switch__track">
        <span class="switch__bg switch__bg--off"></span>
        <span class="switch__bg switch__bg--on"></span>
        <span class="switch__knob"></span>
      </span>
    </label>
    <label class="switch switch--lg is-demo">
      <input type="checkbox" class="switch__input" role="switch" aria-label="Large">
      <span class="switch__track">
        <span class="switch__bg switch__bg--off"></span>
        <span class="switch__bg switch__bg--on"></span>
        <span class="switch__knob"></span>
      </span>
    </label>
  </div>
</main>

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

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

// ── 데모 무대 ───────────────────────────────
@include stage($stage-paper);

.group__title {
  margin: 0 0 clamp(10px, 3vw, 14px);
  color: $subject-ink;
  font-weight: 600; font-size: clamp(13px, 3.6vw, 15px); line-height: 1; font-family: inherit;
  text-align: center;
}
.group {
  display: flex; align-items: center; justify-content: center;
  gap: clamp(14px, 4vw, 20px);
}

.switch {
  position: relative;
  display: inline-flex; align-items: center;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.switch__input {
  position: absolute; inset: 0; width: 100%; height: 100%;
  margin: 0; opacity: 0; cursor: pointer;
}
.switch__track {
  position: relative; overflow: hidden;
  border-radius: $r-pill;
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, .15);
  transition: box-shadow $duration $easing;
}
.switch__bg { position: absolute; inset: 0; }
.switch__bg--off { background: rgba(23, 20, 26, .12); opacity: 1; }
.switch__bg--on  { background: $color; opacity: 0; }
.switch__knob {
  position: absolute; top: 3px; left: 3px; z-index: 1;
  border-radius: 50%;
  background: $stage-paper;
  box-shadow: $shadow-press;
  transform: translateX(0);
  transition: transform $duration cubic-bezier(0.34, 1.56, 0.64, 1);
}

// ── 하나의 믹스인이 폭·높이·이동 거리를 계산한다 ──────────
@mixin switch-size($track-w, $track-h, $knob) {
  --travel: #{$track-w - $knob - 6px};
  .switch__track { width: $track-w; height: $track-h; }
  .switch__knob  { width: $knob; height: $knob; }
}
.switch--sm { @include switch-size(36px, 20px, 14px); }
.switch--md { @include switch-size(48px, 26px, 20px); }
.switch--lg { @include switch-size(60px, 32px, 26px); }

// ── 실제 동작 ─────────────────────────────
.switch__input:checked ~ .switch__track .switch__bg--off { opacity: 0; transition: opacity $duration $easing; }
.switch__input:checked ~ .switch__track .switch__bg--on  { opacity: 1; transition: opacity $duration $easing; }
.switch__input:checked ~ .switch__track .switch__knob    { transform: translateX(var(--travel)); }
.switch__input:checked ~ .switch__track { box-shadow: inset 0 3px 8px rgba(0, 0, 0, .28); }

.switch__input:focus-visible ~ .switch__track {
  outline: 2px solid $subject-ink; outline-offset: 3px;
}

// ── 데모 루프: 세 크기가 같은 keyframes 를 공유한다 ──────
// 한 겹: 노브는 var(--travel) 를 지나쳤다 찌그러지며 안착하고(스프링+squash, 세 크기 공유),
//        트랙 내부 그림자가 상태 전환 때 깊어졌다 얕아진다(세 크기 공유).
.switch.is-demo .switch__bg--off { animation: bg-off-loop $dur-loop $easing infinite; }
.switch.is-demo .switch__bg--on  { animation: bg-on-loop $dur-loop $easing infinite; }
.switch.is-demo .switch__knob    { animation: knob-spring-loop $dur-loop $easing infinite; }
.switch.is-demo .switch__track   { animation: shadow-depth-loop $dur-loop $easing infinite; }

@keyframes bg-off-loop { 0%, 15% { opacity: 1; } 40%, 60% { opacity: 0; } 85%, 100% { opacity: 1; } }
@keyframes bg-on-loop  { 0%, 15% { opacity: 0; } 40%, 60% { opacity: 1; } 85%, 100% { opacity: 0; } }
@keyframes knob-loop {
  0%, 15%   { transform: translateX(0); }
  40%, 60%  { transform: translateX(var(--travel)); }
  85%, 100% { transform: translateX(0); }
}
@keyframes knob-spring-loop {
  0%, 15%   { transform: translateX(0) scaleX(1) scaleY(1); }
  38%       { transform: translateX(calc(var(--travel) + 3px)) scaleX(1.25) scaleY(.85); }  // 오버슈트 + 도착 순간 squash
  43%       { transform: translateX(calc(var(--travel) - 1px)) scaleX(1.08) scaleY(.94); }  // 되튕기며 회복
  47%, 60%  { transform: translateX(var(--travel)) scaleX(1) scaleY(1); }                   // 안착
  84%       { transform: translateX(-2px) scaleX(.92) scaleY(1.06); }                       // 출발 반동
  85%, 100% { transform: translateX(0) scaleX(1) scaleY(1); }
}
@keyframes shadow-depth-loop {
  0%, 15%   { box-shadow: inset 0 1px 3px rgba(0, 0, 0, .15); }
  38%       { box-shadow: inset 0 3px 8px rgba(0, 0, 0, .28); }
  40%, 60%  { box-shadow: inset 0 3px 8px rgba(0, 0, 0, .28); }
  85%, 100% { box-shadow: inset 0 1px 3px rgba(0, 0, 0, .15); }
}

@media (prefers-reduced-motion: reduce) {
  .switch.is-demo .switch__bg--off, .switch.is-demo .switch__bg--on, .switch.is-demo .switch__knob,
  .switch.is-demo .switch__track {
    animation: none !important;
  }
  .switch__bg--off, .switch__bg--on, .switch__knob { transition: 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);
}

.group__title {
  margin: 0 0 clamp(10px, 3vw, 14px);
  color: #17141a;
  font-weight: 600;
  font-size: clamp(13px, 3.6vw, 15px);
  line-height: 1;
  font-family: inherit;
  text-align: center;
}

.group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(14px, 4vw, 20px);
}

.switch {
  position: relative;
  display: inline-flex;
  align-items: center;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.switch__input {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  margin: 0;
  opacity: 0;
  cursor: pointer;
}

.switch__track {
  position: relative;
  overflow: hidden;
  border-radius: 999px;
  box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.15);
  transition: box-shadow 300ms ease-out;
}

.switch__bg {
  position: absolute;
  inset: 0;
}

.switch__bg--off {
  background: rgba(23, 20, 26, 0.12);
  opacity: 1;
}

.switch__bg--on {
  background: #2f6df6;
  opacity: 0;
}

.switch__knob {
  position: absolute;
  top: 3px;
  left: 3px;
  z-index: 1;
  border-radius: 50%;
  background: #ffffff;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  transform: translateX(0);
  transition: transform 300ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.switch--sm {
  --travel: 16px;
}
.switch--sm .switch__track {
  width: 36px;
  height: 20px;
}
.switch--sm .switch__knob {
  width: 14px;
  height: 14px;
}

.switch--md {
  --travel: 22px;
}
.switch--md .switch__track {
  width: 48px;
  height: 26px;
}
.switch--md .switch__knob {
  width: 20px;
  height: 20px;
}

.switch--lg {
  --travel: 28px;
}
.switch--lg .switch__track {
  width: 60px;
  height: 32px;
}
.switch--lg .switch__knob {
  width: 26px;
  height: 26px;
}

.switch__input:checked ~ .switch__track .switch__bg--off {
  opacity: 0;
  transition: opacity 300ms ease-out;
}

.switch__input:checked ~ .switch__track .switch__bg--on {
  opacity: 1;
  transition: opacity 300ms ease-out;
}

.switch__input:checked ~ .switch__track .switch__knob {
  transform: translateX(var(--travel));
}

.switch__input:checked ~ .switch__track {
  box-shadow: inset 0 3px 8px rgba(0, 0, 0, 0.28);
}

.switch__input:focus-visible ~ .switch__track {
  outline: 2px solid #17141a;
  outline-offset: 3px;
}

.switch.is-demo .switch__bg--off {
  animation: bg-off-loop 2s ease-out infinite;
}

.switch.is-demo .switch__bg--on {
  animation: bg-on-loop 2s ease-out infinite;
}

.switch.is-demo .switch__knob {
  animation: knob-spring-loop 2s ease-out infinite;
}

.switch.is-demo .switch__track {
  animation: shadow-depth-loop 2s ease-out infinite;
}

@keyframes bg-off-loop {
  0%, 15% {
    opacity: 1;
  }
  40%, 60% {
    opacity: 0;
  }
  85%, 100% {
    opacity: 1;
  }
}
@keyframes bg-on-loop {
  0%, 15% {
    opacity: 0;
  }
  40%, 60% {
    opacity: 1;
  }
  85%, 100% {
    opacity: 0;
  }
}
@keyframes knob-loop {
  0%, 15% {
    transform: translateX(0);
  }
  40%, 60% {
    transform: translateX(var(--travel));
  }
  85%, 100% {
    transform: translateX(0);
  }
}
@keyframes knob-spring-loop {
  0%, 15% {
    transform: translateX(0) scaleX(1) scaleY(1);
  }
  38% {
    transform: translateX(calc(var(--travel) + 3px)) scaleX(1.25) scaleY(0.85);
  }
  43% {
    transform: translateX(calc(var(--travel) - 1px)) scaleX(1.08) scaleY(0.94);
  }
  47%, 60% {
    transform: translateX(var(--travel)) scaleX(1) scaleY(1);
  }
  84% {
    transform: translateX(-2px) scaleX(0.92) scaleY(1.06);
  }
  85%, 100% {
    transform: translateX(0) scaleX(1) scaleY(1);
  }
}
@keyframes shadow-depth-loop {
  0%, 15% {
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.15);
  }
  38% {
    box-shadow: inset 0 3px 8px rgba(0, 0, 0, 0.28);
  }
  40%, 60% {
    box-shadow: inset 0 3px 8px rgba(0, 0, 0, 0.28);
  }
  85%, 100% {
    box-shadow: inset 0 1px 3px rgba(0, 0, 0, 0.15);
  }
}
@media (prefers-reduced-motion: reduce) {
  .switch.is-demo .switch__bg--off, .switch.is-demo .switch__bg--on, .switch.is-demo .switch__knob,
  .switch.is-demo .switch__track {
    animation: none !important;
  }
  .switch__bg--off, .switch__bg--on, .switch__knob {
    transition: none;
  }
}

document.querySelectorAll(".switch").forEach(function (s) {
  var input = s.querySelector(".switch__input");
  var sync = function () { input.setAttribute("aria-checked", String(input.checked)); };
  input.addEventListener("pointerdown", function () { s.classList.remove("is-demo"); });
  input.addEventListener("change", sync);
  sync();
});

import { useState } from "react";
import type { ChangeEvent, CSSProperties } from "react";
import styles from "./SizeVariantToggle.module.scss";

export type SizeVariantToggleProps = {
  label?: string;
  size?: "sm" | "md" | "lg";
  duration?: number;
  easing?: string;
  color?: string;
  defaultChecked?: boolean;
  onChange?: (checked: boolean) => void;
};

const SIZES = {
  sm: { track: "36px", height: "20px", knob: "14px", travel: "16px" },
  md: { track: "48px", height: "26px", knob: "20px", travel: "22px" },
  lg: { track: "60px", height: "32px", knob: "26px", travel: "28px" },
} as const;

type Vars = CSSProperties & {
  "--duration"?: string; "--easing"?: string; "--color"?: string;
  "--track-w"?: string; "--track-h"?: string; "--knob"?: string; "--travel"?: string;
};

export default function SizeVariantToggle({
  label,
  size = "md",
  duration = 300,
  easing = "ease-out",
  color = "#2f6df6",
  defaultChecked = false,
  onChange,
}: SizeVariantToggleProps) {
  const [checked, setChecked] = useState(defaultChecked);
  const s = SIZES[size];
  const vars: Vars = {
    "--duration": `${duration}ms`, "--easing": easing, "--color": color,
    "--track-w": s.track, "--track-h": s.height, "--knob": s.knob, "--travel": s.travel,
  };

  return (
    <label className={styles.switch} style={vars}>
      <input
        type="checkbox"
        role="switch"
        aria-label={label ?? size}
        aria-checked={checked}
        className={styles.switch__input}
        checked={checked}
        onChange={(e: ChangeEvent<HTMLInputElement>) => { setChecked(e.target.checked); onChange?.(e.target.checked); }}
      />
      <span className={styles.switch__track}>
        <span className={styles["switch__bg--off"]} />
        <span className={styles["switch__bg--on"]} />
        <span className={styles.switch__knob} />
      </span>
    </label>
  );
}