05Size chip + quantity stepper combo

<main class="stage">
  <div class="sq is-demo">
    <div class="sq__sizes" role="radiogroup" aria-label="Select a size">
      <label class="sq__chip"><input type="radio" name="size" value="S" class="sq__radio" data-price="19000"><span>S</span></label>
      <label class="sq__chip"><input type="radio" name="size" value="M" class="sq__radio" data-price="19000" checked><span>M</span></label>
      <label class="sq__chip"><input type="radio" name="size" value="L" class="sq__radio" data-price="20000"><span>L</span></label>
      <label class="sq__chip"><input type="radio" name="size" value="XL" class="sq__radio" data-price="21000"><span>XL</span></label>
    </div>
    <div class="sq__qty">
      <button type="button" class="sq__btn" id="dec" aria-label="Decrease quantity">−</button>
      <span class="sq__num" id="num" aria-live="polite">1</span>
      <button type="button" class="sq__btn" id="inc" aria-label="Increase quantity">+</button>
    </div>
    <div class="sq__total">Subtotal <strong id="total">19,000 KRW</strong></div>
  </div>
</main>

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

// ── 변수 3개 ──────────────────────────────
$duration: $dur-quick;
$easing: $ease-pop;
$color: $subject-mint;

@include stage($stage-paper);

.sq { display: flex; flex-direction: column; align-items: center; gap: $sp-4; color: $subject-ink; }
.sq__sizes { display: flex; gap: $sp-2; }
.sq__chip { position: relative; }
.sq__radio { position: absolute; opacity: 0; width: 1px; height: 1px; }
.sq__chip span {
  display: grid; place-items: center; width: 36px; height: 32px; border-radius: $r-control;
  border: 1px solid rgba($subject-ink, .18); font-size: 13px; font-weight: 700; cursor: pointer;
  transition: transform $duration $easing, background-color $duration $easing, color $duration $easing, border-color $duration $easing;
}
.sq__radio:checked ~ span {
  background: $color; border-color: $color; color: #fff; transform: scale(1.08);
}
.sq__radio:focus-visible ~ span { outline: 2px solid $subject-ink; outline-offset: 2px; }

.sq__qty { display: flex; align-items: center; gap: $sp-3; }
.sq__btn {
  appearance: none; border: 1px solid rgba($subject-ink, .2); background: #fff;
  width: 30px; height: 30px; border-radius: 50%; font-size: 16px; line-height: 1; cursor: pointer;
  transition: transform $duration $easing, opacity $duration $easing;
}
.sq__btn:active { transform: scale(.9); }
.sq__btn:disabled { opacity: .3; cursor: not-allowed; }
.sq__num { min-width: 24px; text-align: center; font-weight: 700; font-size: 15px; }
.sq__total { font-size: 13px; color: rgba($subject-ink, .7); }
.sq__total strong { color: $subject-ink; }

@media (prefers-reduced-motion: reduce) {
  .sq__chip span, .sq__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: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.sq {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  color: #17141a;
}

.sq__sizes {
  display: flex;
  gap: 8px;
}

.sq__chip {
  position: relative;
}

.sq__radio {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
}

.sq__chip span {
  display: grid;
  place-items: center;
  width: 36px;
  height: 32px;
  border-radius: 12px;
  border: 1px solid rgba(23, 20, 26, 0.18);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1), background-color 220ms cubic-bezier(0.2, 1.4, 0.4, 1), color 220ms cubic-bezier(0.2, 1.4, 0.4, 1), border-color 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.sq__radio:checked ~ span {
  background: #4cd4a6;
  border-color: #4cd4a6;
  color: #fff;
  transform: scale(1.08);
}

.sq__radio:focus-visible ~ span {
  outline: 2px solid #17141a;
  outline-offset: 2px;
}

.sq__qty {
  display: flex;
  align-items: center;
  gap: 12px;
}

.sq__btn {
  appearance: none;
  border: 1px solid rgba(23, 20, 26, 0.2);
  background: #fff;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  font-size: 16px;
  line-height: 1;
  cursor: pointer;
  transition: transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1), opacity 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.sq__btn:active {
  transform: scale(0.9);
}

.sq__btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.sq__num {
  min-width: 24px;
  text-align: center;
  font-weight: 700;
  font-size: 15px;
}

.sq__total {
  font-size: 13px;
  color: rgba(23, 20, 26, 0.7);
}

.sq__total strong {
  color: #17141a;
}

@media (prefers-reduced-motion: reduce) {
  .sq__chip span, .sq__btn {
    transition: none;
  }
}

(function () {
  var sq = document.querySelector('.sq');
  var radios = Array.prototype.slice.call(sq.querySelectorAll('.sq__radio'));
  var dec = document.getElementById('dec'), inc = document.getElementById('inc'),
      num = document.getElementById('num'), total = document.getElementById('total');
  var qty = 1;
  function price() { return +(radios.filter(function (r) { return r.checked; })[0] || radios[0]).dataset.price; }
  function paint() {
    num.textContent = qty;
    dec.disabled = qty <= 1; inc.disabled = qty >= 9;
    total.textContent = (price() * qty).toLocaleString('ko-KR') + ' KRW';
  }
  radios.forEach(function (r) { r.addEventListener('change', function () { stop(); paint(); }); });
  dec.addEventListener('click', function () { stop(); qty = Math.max(1, qty - 1); paint(); });
  inc.addEventListener('click', function () { stop(); qty = Math.min(9, qty + 1); paint(); });

  var seq = [[1, 1], [3, 1], [3, 3], [0, 2], [2, 4]], si = 0;
  var t = setInterval(function () {
    var s = seq[si % seq.length];
    radios[s[0]].checked = true; qty = s[1]; paint(); si++;
  }, 600);
  function stop() { sq.classList.remove('is-demo'); clearInterval(t); }
  paint();
}());

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

type Size = { label: string; price: number };

export type SizeQuantityChipStepperProps = {
  sizes?: Size[];
  duration?: number;
  easing?: string;
  color?: string;
};

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

const DEFAULT_SIZES: Size[] = [
  { label: "S", price: 19000 },
  { label: "M", price: 19000 },
  { label: "L", price: 20000 },
  { label: "XL", price: 21000 },
];

export default function SizeQuantityChipStepper({
  sizes = DEFAULT_SIZES,
  duration = 220,
  easing = "cubic-bezier(.2,1.4,.4,1)",
  color = "#4cd4a6",
}: SizeQuantityChipStepperProps) {
  const [sizeIdx, setSizeIdx] = useState(1);
  const [qty, setQty] = useState(1);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--c": color };
  const total = sizes[sizeIdx].price * qty;

  return (
    <div className={styles.sq} style={vars}>
      <div className={styles.sizes} role="radiogroup" aria-label="Select a size">
        {sizes.map((s, i) => (
          <label key={s.label} className={styles.chip}>
            <input type="radio" name="size" className={styles.radio} checked={sizeIdx === i}
              onChange={() => setSizeIdx(i)} />
            <span data-on={sizeIdx === i}>{s.label}</span>
          </label>
        ))}
      </div>
      <div className={styles.qty}>
        <button type="button" className={styles.btn} aria-label="Decrease quantity"
          disabled={qty <= 1} onClick={() => setQty((q) => Math.max(1, q - 1))}>−</button>
        <span className={styles.num} aria-live="polite">{qty}</span>
        <button type="button" className={styles.btn} aria-label="Increase quantity"
          disabled={qty >= 9} onClick={() => setQty((q) => Math.min(9, q + 1))}>+</button>
      </div>
      <div className={styles.total}>Subtotal <strong>{total.toLocaleString("en-US")} KRW</strong></div>
    </div>
  );
}