04Monthly/yearly toggle

<main class="stage">
  <div class="mt-wrap">
    <div class="mt-toggle is-demo">
      <input type="radio" name="mt-period" id="mt-monthly" class="mt-radio mt-radio--m" checked>
      <input type="radio" name="mt-period" id="mt-yearly" class="mt-radio mt-radio--y">
      <label class="mt-option" for="mt-monthly">Monthly</label>
      <label class="mt-option" for="mt-yearly">Yearly</label>
      <span class="mt-indicator" aria-hidden="true"></span>
    </div>
    <div class="mt-price">$29<span class="mt-price__unit">/mo</span></div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-base;
$easing: $ease-spring;
$color: $subject-blue-deep;   // 크림 글자가 얹히므로 진한 파랑

@include stage($stage-paper);

.mt-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-6;
}

.mt-toggle {
  position: relative;
  display: flex;
  width: min(220px, 78vw);
  border-radius: $r-pill;
  background: rgba(23, 20, 26, .06);
  padding: $sp-1;
  box-sizing: border-box;
}

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

.mt-option {
  position: relative;
  z-index: 1;
  flex: 1 1 0;
  text-align: center;
  padding: $sp-2 0;
  border-radius: $r-pill;
  cursor: pointer;
  color: $subject-ink;
  font: 600 12px/1 -apple-system, "Segoe UI", sans-serif;
}

// 인디케이터는 두 옵션과 같은 50/50 분할을 쓴다 — flex 로 갈린 실제 폭을 짐작한 px 로 흉내내지 않는다 (BD19)
.mt-indicator {
  position: absolute;
  top: $sp-1;
  left: $sp-1;
  width: calc(50% - #{$sp-1});
  height: calc(100% - #{$sp-1} * 2);
  border-radius: $r-pill;
  background: $color;
  box-shadow: $shadow-press;
  transition: transform $duration $easing;
}
#mt-yearly:checked ~ .mt-indicator { transform: translateX(100%); }
#mt-yearly:checked ~ .mt-option[for="mt-yearly"] { color: $subject-cream; }
#mt-monthly:checked ~ .mt-option[for="mt-monthly"] { color: $subject-cream; }

.mt-price { font: 700 26px/1 -apple-system, "Segoe UI", sans-serif; color: $subject-ink; }
.mt-price__unit { font-size: 13px; font-weight: 500; opacity: .6; }

// 데모 루프: 헤드리스는 라디오를 못 눌러 is-demo 가 같은 이동을 keyframes 로 반복한다 (캡처용)
@keyframes mt-slide {
  0%, 40% { transform: translateX(0); }
  60%, 100% { transform: translateX(100%); }
}
.mt-toggle.is-demo .mt-indicator { animation: mt-slide $duration * 3 $easing infinite; }

@media (prefers-reduced-motion: reduce) {
  .mt-indicator,
  .mt-toggle.is-demo .mt-indicator { animation: none !important; transition: 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);
}

.mt-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
}

.mt-toggle {
  position: relative;
  display: flex;
  width: min(220px, 78vw);
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.06);
  padding: 4px;
  box-sizing: border-box;
}

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

.mt-option {
  position: relative;
  z-index: 1;
  flex: 1 1 0;
  text-align: center;
  padding: 8px 0;
  border-radius: 999px;
  cursor: pointer;
  color: #17141a;
  font: 600 12px/1 -apple-system, "Segoe UI", sans-serif;
}

.mt-indicator {
  position: absolute;
  top: 4px;
  left: 4px;
  width: calc(50% - 4px);
  height: calc(100% - 4px * 2);
  border-radius: 999px;
  background: #0a4fe8;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  transition: transform 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

#mt-yearly:checked ~ .mt-indicator {
  transform: translateX(100%);
}

#mt-yearly:checked ~ .mt-option[for=mt-yearly] {
  color: #fff7e6;
}

#mt-monthly:checked ~ .mt-option[for=mt-monthly] {
  color: #fff7e6;
}

.mt-price {
  font: 700 26px/1 -apple-system, "Segoe UI", sans-serif;
  color: #17141a;
}

.mt-price__unit {
  font-size: 13px;
  font-weight: 500;
  opacity: 0.6;
}

@keyframes mt-slide {
  0%, 40% {
    transform: translateX(0);
  }
  60%, 100% {
    transform: translateX(100%);
  }
}
.mt-toggle.is-demo .mt-indicator {
  animation: mt-slide 900ms cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}

@media (prefers-reduced-motion: reduce) {
  .mt-indicator,
  .mt-toggle.is-demo .mt-indicator {
    animation: none !important;
    transition: none !important;
  }
}

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

export interface MonthlyYearlyToggleProps {
  duration?: string;
  easing?: string;
  color?: string;
  name?: string;
}

// 실사용: 숨긴 라디오 두 개 + 일반 형제 선택자. 자바스크립트로 상태를 들지 않는다.
export default function MonthlyYearlyToggle({
  duration = "300ms",
  easing = "cubic-bezier(.2, .8, .2, 1)",
  color = "#0a4fe8",
  name = "mt-period",
}: MonthlyYearlyToggleProps) {
  const monthlyId = `${name}-monthly`;
  const yearlyId = `${name}-yearly`;
  const style = { "--duration": duration, "--easing": easing, "--color": color } as CSSProperties;

  return (
    <div className={styles.wrap} style={style}>
      <div className={styles.toggle}>
        <input type="radio" name={name} id={monthlyId} className={styles.radio} defaultChecked />
        <input type="radio" name={name} id={yearlyId} className={styles.radio} />
        <label className={styles.option} htmlFor={monthlyId}>Monthly</label>
        <label className={styles.option} htmlFor={yearlyId}>Yearly</label>
        <span className={styles.indicator} aria-hidden="true" />
      </div>
      <div className={styles.price}>$29<span className={styles.unit}>/mo</span></div>
    </div>
  );
}