03Corner-rounding value growth — the more the open value grows, the more the button's corner rounding grows with it

<main class="stage">
<div class="cr is-demo" id="cr">
  <div class="cr__meter" aria-hidden="true">
    <div class="cr__meterFill" id="crFill"></div>
  </div>
  <p class="cr__read" id="crRead">Rounding value 12px</p>
  <div class="cr__btn" id="crBtn" role="button" tabindex="0" aria-label="Raise step value">
    <span class="cr__label">Next step</span>
  </div>
  <div class="cr__steps" aria-hidden="true">
    <span class="cr__dot"></span>
    <span class="cr__dot"></span>
    <span class="cr__dot"></span>
    <span class="cr__dot"></span>
  </div>
</div>
</main>

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

// 계산 겹: 단계 값마다 둥근 반경이 RADII 산술(12→16→24→알약)으로 커지고(index.html),
// 크기 성장 곡선이 같은 transition 에 물려 함께 이어진다.
@include stage($stage-orange);

.cr {
  display: grid;
  gap: $sp-4;
  justify-items: center;
}

.cr__meter {
  width: 220px;
  height: $sp-1;
  border-radius: $r-xs;
  background: rgba($subject-cream, .22);
  overflow: hidden;
}

.cr__meterFill {
  width: 100%;
  height: 100%;
  border-radius: $r-xs;
  background: $subject-cream;
  transform-origin: left center;
  transform: scaleX(.25);
  transition: transform $dur-base $ease-out;
}

.cr__read {
  margin: 0;
  color: $subject-ink;
  font-size: 13px;
  font-weight: 600;
}

.cr__btn {
  display: grid;
  place-items: center;
  width: 200px;
  height: 64px;
  border-radius: $r-control;
  background: $stage-paper;
  color: $subject-ink;
  box-shadow: $shadow-raised;
  cursor: pointer;
  transition: border-radius $dur-enter $ease-elastic, width $dur-enter $ease-elastic, height $dur-enter $ease-elastic;
}

.cr__label {
  font-weight: 700;
  font-size: 16px;
}

.cr__steps {
  display: flex;
  gap: $sp-2;
}

.cr__dot {
  width: $sp-2;
  height: $sp-2;
  border-radius: 50%;
  background: rgba($subject-cream, .28);
  transition: background-color $dur-quick $ease-out, transform $dur-quick $ease-elastic;
}

.cr__dot--on {
  background: $stage-paper;
  transform: scale(1.18);
}

@media (max-width: 340px) {
  .cr__btn { width: 180px; height: 56px; }
  .cr__meter { width: 180px; }
}

@media (prefers-reduced-motion: reduce) {
  .cr__btn, .cr__meterFill, .cr__dot { transition: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.cr {
  display: grid;
  gap: 16px;
  justify-items: center;
}

.cr__meter {
  width: 220px;
  height: 4px;
  border-radius: 4px;
  background: rgba(255, 247, 230, 0.22);
  overflow: hidden;
}

.cr__meterFill {
  width: 100%;
  height: 100%;
  border-radius: 4px;
  background: #fff7e6;
  transform-origin: left center;
  transform: scaleX(0.25);
  transition: transform 300ms ease-out;
}

.cr__read {
  margin: 0;
  color: #17141a;
  font-size: 13px;
  font-weight: 600;
}

.cr__btn {
  display: grid;
  place-items: center;
  width: 200px;
  height: 64px;
  border-radius: 12px;
  background: #ffffff;
  color: #17141a;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  cursor: pointer;
  transition: border-radius 600ms cubic-bezier(0.34, 1.56, 0.64, 1), width 600ms cubic-bezier(0.34, 1.56, 0.64, 1), height 600ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.cr__label {
  font-weight: 700;
  font-size: 16px;
}

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

.cr__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255, 247, 230, 0.28);
  transition: background-color 220ms ease-out, transform 220ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

.cr__dot--on {
  background: #ffffff;
  transform: scale(1.18);
}

@media (max-width: 340px) {
  .cr__btn {
    width: 180px;
    height: 56px;
  }
  .cr__meter {
    width: 180px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .cr__btn, .cr__meterFill, .cr__dot {
    transition: none;
  }
}

(function () {
  var root = document.getElementById('cr');
  var btn = document.getElementById('crBtn');
  var fill = document.getElementById('crFill');
  var read = document.getElementById('crRead');
  var dots = root.querySelectorAll('.cr__dot');
  var RADII = [12, 16, 24, 999]; // 계산 겹: 단계마다 커지는 둥근 값(px) — 마지막은 pill
  var RADII_TEXT = ['Rounding value 12px', 'Rounding value 16px', 'Rounding value 24px', 'Rounding value pill'];
  var step = 0;

  function paint() {
    var r = RADII[step];
    // 둥근 값은 % 가 아니라 px 로 보간해야 성장이 선형으로 보인다 — 999px 는 pill 표기
    btn.style.borderRadius = (r === 999 ? '999px' : r + 'px');
    read.textContent = RADII_TEXT[step];
    fill.style.transform = 'scaleX(' + ((step + 1) / RADII.length) + ')';
    dots.forEach(function (d, i) {
      d.classList.toggle('cr__dot--on', i <= step);
    });
  }

  function advance() {
    step = (step + 1) % RADII.length;
    paint();
  }

  function human() {
    root.classList.remove('is-demo');
    stopAutoplay();
    advance();
  }
  btn.addEventListener('click', human);
  btn.addEventListener('keydown', function (e) {
    if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); human(); }
  });

  var autoTimer = null;
  function stopAutoplay() { if (autoTimer) { clearInterval(autoTimer); autoTimer = null; } }
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  paint();
  if (!reduce) { autoTimer = setInterval(advance, 900); }
})();

import { useEffect, useRef } from "react";
import styles from "./CornerRoundGrow.module.scss";

type Box<T> = { current: T };

const RADII = [12, 16, 24, 999]; // 계산 겹: 단계마다 커지는 둥근 값(px) — 마지막은 알약
const RADII_TEXT = ["둥근 값 12px", "둥근 값 16px", "둥근 값 24px", "둥근 값 알약"];

export default function CornerRoundGrow() {
  const rootRef = useRef(null) as unknown as Box<HTMLDivElement | null>;

  useEffect(() => {
    const root = rootRef.current;
    if (!root) return;
    const btn = root.querySelector(`.${styles.btn}`) as HTMLElement | null;
    const fill = root.querySelector(`.${styles.fill}`) as HTMLElement | null;
    const read = root.querySelector(`.${styles.read}`) as HTMLElement | null;
    const dots = root.querySelectorAll(`.${styles.dot}`);
    if (!btn || !fill || !read) return;

    let step = 0;

    function paint() {
      const r = RADII[step];
      btn!.style.borderRadius = (r === 999 ? "999px" : r + "px");
      read!.textContent = RADII_TEXT[step];
      fill!.style.transform = "scaleX(" + ((step + 1) / RADII.length) + ")";
      dots.forEach((d, i) => {
        d.classList.toggle(styles["dot--on"], i <= step);
      });
    }

    function advance() {
      step = (step + 1) % RADII.length;
      paint();
    }

    function human() {
      root!.classList.remove(styles["is-demo"]);
      stopAutoplay();
      advance();
    }
    function onClick() { human(); }
    function onKey(e: KeyboardEvent) {
      if (e.key === "Enter" || e.key === " ") { e.preventDefault(); human(); }
    }
    btn.addEventListener("click", onClick);
    btn.addEventListener("keydown", onKey);

    let autoTimer: number | null = null;
    function stopAutoplay() { if (autoTimer !== null) { window.clearInterval(autoTimer); autoTimer = null; } }
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    paint();
    if (!reduce) { autoTimer = window.setInterval(advance, 900); }

    return () => {
      stopAutoplay();
      btn.removeEventListener("click", onClick);
      btn.removeEventListener("keydown", onKey);
    };
  }, []);

  return (
    <div ref={rootRef} className={`${styles.stage} ${styles.cr} ${styles["is-demo"]}`}>
      <div className={styles.meter} aria-hidden="true">
        <div className={styles.fill} />
      </div>
      <p className={styles.read}>둥근 값 12px</p>
      <div className={styles.btn} role="button" tabIndex={0} aria-label="단계 값 올리기">
        <span className={styles.label}>다음 단계</span>
      </div>
      <div className={styles.steps} aria-hidden="true">
        <span className={styles.dot} />
        <span className={styles.dot} />
        <span className={styles.dot} />
        <span className={styles.dot} />
      </div>
    </div>
  );
}