05Industry tabs — tabs that recount per-industry totals on every switch

<main class="stage">
<section class="panel">
  <p class="hint" id="hint">Try clicking a tab — the underline doesn't guess a value, it measures the pressed tab's actual rendered width every time and moves there.</p>
  <div class="tabsWrap">
    <div class="tabs" id="tabs" role="tablist" aria-label="Industry">
      <button class="tab" id="tab-0" role="tab" aria-selected="true" data-idx="0">E-commerce</button>
      <button class="tab" id="tab-1" role="tab" aria-selected="false" data-idx="1">Fintech</button>
      <button class="tab" id="tab-2" role="tab" aria-selected="false" data-idx="2">Healthcare</button>
      <button class="tab" id="tab-3" role="tab" aria-selected="false" data-idx="3">Education</button>
    </div>
    <div class="underline" id="underline"></div>
  </div>
  <p class="countRow">
    <span class="countNum" id="countNum">12</span>
    <span class="countLabel" id="countLabel">E-commerce cases · 28% of 43 total</span>
  </p>
</section>
</main>

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

$duration: $dur-base;
$easing: $ease-spring;
$color: $subject-blue-light;

@include stage($stage-ink);

.panel {
  width: 100%;
  max-width: 380px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-3;
  text-align: center;
}

.hint {
  margin: 0;
  color: rgba($subject-cream, .72);
  font-weight: 400;
  font-size: 10px;
  line-height: 1.35;
}

.tabsWrap {
  position: relative;
  width: 100%;
}

.tabs {
  position: relative;
  display: flex;
  gap: $sp-3;
  padding-bottom: $sp-2;
  border-bottom: 1px solid rgba($subject-cream, .16);
}

.tab {
  flex: 0 0 auto;
  appearance: none;
  border: 0;
  background: transparent;
  padding: $sp-1 $sp-1;
  color: rgba($subject-cream, .72);
  font-weight: 600;
  font-size: 12px;
  cursor: pointer;

  &[aria-selected="true"] {
    color: $subject-cream;
  }

  &:focus-visible {
    outline: 2px solid $color;
    outline-offset: 2px;
  }
}

.underline {
  position: absolute;
  left: 0;
  bottom: 0;
  height: 2px;
  width: 1px;
  background: $color;
  transform: translateX(0) scaleX(1);
  transition: transform $duration $easing;
}

.countRow {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: $sp-1;
}

.countNum {
  color: $subject-cream;
  font-weight: 700;
  font-size: 22px;
  font-variant-numeric: tabular-nums;
}

.countLabel {
  color: rgba($subject-cream, .72);
  font-weight: 500;
  font-size: 11px;
}

@media (max-width: 340px) {
  .panel { max-width: 300px; gap: $sp-2; }
  .tabs { gap: $sp-2; }
  .tab { font-size: 10px; }
  .countNum { font-size: 18px; }
  .countLabel { font-size: 9px; }
  .hint { font-size: 9px; }
}

@media (prefers-reduced-motion: reduce) {
  .underline {
    transition: none;
  }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.panel {
  width: 100%;
  max-width: 380px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  text-align: center;
}

.hint {
  margin: 0;
  color: rgba(255, 247, 230, 0.72);
  font-weight: 400;
  font-size: 10px;
  line-height: 1.35;
}

.tabsWrap {
  position: relative;
  width: 100%;
}

.tabs {
  position: relative;
  display: flex;
  gap: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(255, 247, 230, 0.16);
}

.tab {
  flex: 0 0 auto;
  appearance: none;
  border: 0;
  background: transparent;
  padding: 4px 4px;
  color: rgba(255, 247, 230, 0.72);
  font-weight: 600;
  font-size: 12px;
  cursor: pointer;
}
.tab[aria-selected=true] {
  color: #fff7e6;
}
.tab:focus-visible {
  outline: 2px solid #5b8cf8;
  outline-offset: 2px;
}

.underline {
  position: absolute;
  left: 0;
  bottom: 0;
  height: 2px;
  width: 1px;
  background: #5b8cf8;
  transform: translateX(0) scaleX(1);
  transition: transform 300ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.countRow {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.countNum {
  color: #fff7e6;
  font-weight: 700;
  font-size: 22px;
  font-variant-numeric: tabular-nums;
}

.countLabel {
  color: rgba(255, 247, 230, 0.72);
  font-weight: 500;
  font-size: 11px;
}

@media (max-width: 340px) {
  .panel {
    max-width: 300px;
    gap: 8px;
  }
  .tabs {
    gap: 8px;
  }
  .tab {
    font-size: 10px;
  }
  .countNum {
    font-size: 18px;
  }
  .countLabel {
    font-size: 9px;
  }
  .hint {
    font-size: 9px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .underline {
    transition: none;
  }
}

// Industry 탭(05) — 실제 클릭 이벤트로 탭을 바꾼다. 밑줄은 고정 px 를 미리 적어두지 않고,
// 눌린 탭을 getBoundingClientRect 로 매번 실측해 translateX/scaleX 로 옮긴다(BD19).
// 사례 수도 매번 전체 대비 비율을 다시 나눠 구한다(계산 한 겹).
(function () {
  var tabsEl = document.getElementById('tabs');
  var underlineEl = document.getElementById('underline');
  var countNumEl = document.getElementById('countNum');
  var countLabelEl = document.getElementById('countLabel');
  if (!tabsEl || !underlineEl || !countNumEl || !countLabelEl) return;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var TABS = [
    { label: 'E-commerce', count: 12 },
    { label: 'Fintech', count: 9 },
    { label: 'Healthcare', count: 15 },
    { label: 'Education', count: 7 }
  ];
  var TOTAL = TABS.reduce(function (sum, t) { return sum + t.count; }, 0);
  var buttons = Array.prototype.slice.call(tabsEl.querySelectorAll('.tab'));
  var current = 0;

  function measureAndMove(idx) {
    var btn = buttons[idx];
    var wrapRect = tabsEl.getBoundingClientRect();
    var btnRect = btn.getBoundingClientRect();
    var x = btnRect.left - wrapRect.left;
    var w = btnRect.width;
    underlineEl.style.transform = 'translateX(' + x.toFixed(2) + 'px) scaleX(' + w.toFixed(2) + ')';
  }

  function selectTab(idx) {
    current = idx;
    buttons.forEach(function (b, i) {
      b.setAttribute('aria-selected', i === idx ? 'true' : 'false');
    });
    var tab = TABS[idx];
    var percent = Math.round((tab.count / TOTAL) * 100);
    countNumEl.textContent = String(tab.count);
    countLabelEl.textContent = '  ' + tab.label + '  cases ·  ' + TOTAL + ' total,  ' + percent + '%';
    measureAndMove(idx);
  }

  buttons.forEach(function (btn, i) {
    btn.addEventListener('click', function () {
      selectTab(i);
    });
  });

  underlineEl.style.transformOrigin = 'left center';
  requestAnimationFrame(function () { selectTab(0); });

  if (!reduce) {
    setInterval(function () {
      selectTab((current + 1) % TABS.length);
    }, 500);
  }

  window.addEventListener('resize', function () { measureAndMove(current); });
})();

// CaseIndustryTabs — vanilla 판(run/340/demo/05-case-industry-tabs/index.html) 의 React 포트.
// 실제 클릭 이벤트로 탭을 바꾼다. 밑줄은 고정 px 를 미리 적어두지 않고 눌린 탭을
// getBoundingClientRect 로 매번 실측해 translateX/scaleX 로 옮긴다(BD19). 사례 수도
// 매번 전체 대비 비율을 다시 나눠 구한다.
import { useEffect, useRef } from "react";
import styles from "./CaseIndustryTabs.module.scss";

export type CaseIndustryTabsProps = {
  duration?: string;
  easing?: string;
  color?: string;
};

const HINT = "탭을 눌러 보세요 — 밑줄은 짐작한 값이 아니라 눌린 탭의 실제 렌더 폭을 매번 재서 그 자리로 옮깁니다";

type Tab = { label: string; count: number };

const TABS: Tab[] = [
  { label: "이커머스", count: 12 },
  { label: "핀테크", count: 9 },
  { label: "헬스케어", count: 15 },
  { label: "교육", count: 7 }
];

const TOTAL = TABS.reduce((sum, t) => sum + t.count, 0);

export default function CaseIndustryTabs({
  duration = "220ms",
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#5b8cf8"
}: CaseIndustryTabsProps) {
  const tabsRef = useRef<HTMLDivElement | null>(null);
  const underlineRef = useRef<HTMLDivElement | null>(null);
  const countNumRef = useRef<HTMLSpanElement | null>(null);
  const countLabelRef = useRef<HTMLSpanElement | null>(null);
  const btnRefs = useRef<(HTMLButtonElement | null)[]>([]);
  const currentRef = useRef(0);

  useEffect(() => {
    const tabsEl = tabsRef.current;
    const underlineEl = underlineRef.current;
    const countNumEl = countNumRef.current;
    const countLabelEl = countLabelRef.current;
    if (!tabsEl || !underlineEl || !countNumEl || !countLabelEl) return;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    function measureAndMove(idx: number): void {
      const btn = btnRefs.current![idx];
      if (!btn) return;
      const wrapRect = tabsEl!.getBoundingClientRect();
      const btnRect = btn.getBoundingClientRect();
      const x = btnRect.left - wrapRect.left;
      const w = btnRect.width;
      underlineEl!.style.transform = "translateX(" + x.toFixed(2) + "px) scaleX(" + w.toFixed(2) + ")";
    }

    function selectTab(idx: number): void {
      currentRef.current = idx;
      btnRefs.current!.forEach((b, i) => {
        if (b) b.setAttribute("aria-selected", i === idx ? "true" : "false");
      });
      const tab = TABS[idx];
      const percent = Math.round((tab.count / TOTAL) * 100);
      countNumEl!.textContent = String(tab.count);
      countLabelEl!.textContent = "개 " + tab.label + " 사례 · 전체 " + TOTAL + "개 중 " + percent + "%";
      measureAndMove(idx);
    }

    const handlers: Array<() => void> = [];
    btnRefs.current!.forEach((btn, i) => {
      if (!btn) return;
      const handler = () => selectTab(i);
      handlers[i] = handler;
      btn.addEventListener("click", handler);
    });

    underlineEl.style.transformOrigin = "left center";
    const raf = requestAnimationFrame(() => selectTab(0));

    let timer = 0;
    if (!reduce) {
      timer = window.setInterval(() => {
        selectTab((currentRef.current! + 1) % TABS.length);
      }, 500);
    }

    const onResize = () => measureAndMove(currentRef.current!);
    window.addEventListener("resize", onResize);

    return () => {
      cancelAnimationFrame(raf);
      if (timer) window.clearInterval(timer);
      window.removeEventListener("resize", onResize);
      btnRefs.current!.forEach((btn, i) => {
        if (btn && handlers[i]) btn.removeEventListener("click", handlers[i]);
      });
    };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  return (
    <main className={styles.stage}>
      <section className={styles.panel}>
        <p className={styles.hint}>{HINT}</p>
        <div className={styles.tabsWrap}>
          <div className={styles.tabs} ref={tabsRef} role="tablist" aria-label="업종">
            {TABS.map((tab, i) => (
              <button
                key={tab.label}
                className={styles.tab}
                role="tab"
                aria-selected={i === 0}
                ref={(el: HTMLButtonElement | null) => {
                  btnRefs.current![i] = el;
                }}
              >
                {tab.label}
              </button>
            ))}
          </div>
          <div className={styles.underline} ref={underlineRef} />
        </div>
        <p className={styles.countRow}>
          <span className={styles.countNum} ref={countNumRef}>12</span>
          <span className={styles.countLabel} ref={countLabelRef}>개 이커머스 사례 · 전체 43개 중 28%</span>
        </p>
      </section>
    </main>
  );
}