03Current page emphasis

<main class="stage">
  <div class="ce is-demo">
    <nav aria-label="Breadcrumb">
      <ol class="ce__list">
        <li><a class="ce__crumb" href="#">Home</a></li>
        <li><a class="ce__crumb" href="#">Electronics</a></li>
        <li><a class="ce__crumb" href="#">Laptops</a></li>
        <li><span class="ce__crumb ce__cur" aria-current="page">13-inch gaming</span></li>
      </ol>
    </nav>
    <p class="ce__say" aria-live="polite">
      <svg viewBox="0 0 256 256" width="14" height="14" aria-hidden="true"><g fill="currentColor"><path d="M224 128a96 96 0 1 1-96-96a96 96 0 0 1 96 96" opacity=".2"/><path d="M173.66 98.34a8 8 0 0 1 0 11.32l-56 56a8 8 0 0 1-11.32 0l-24-24a8 8 0 0 1 11.32-11.32L112 148.69l50.34-50.35a8 8 0 0 1 11.32 0M232 128A104 104 0 1 1 128 24a104.11 104.11 0 0 1 104 104m-16 0a88 88 0 1 0-88 88a88.1 88.1 0 0 0 88-88"/></g></svg><span class="ce__lab">Current page</span> · <span class="ce__val">13-inch gaming</span>
    </p>
  </div>
</main>

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

$duration: $dur-enter;
$easing: $ease-spring;
$color: $subject-ink;

@include stage($stage-yellow);

.ce {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-6;
  user-select: none;
  -webkit-user-select: none;
}

.ce__list {
  display: flex;
  align-items: center;
  flex-wrap: nowrap;
  gap: $sp-2;
  margin: 0;
  padding: 0;
  list-style: none;
  white-space: nowrap;
  font-size: clamp(11px, 3.2vw, 14px);
  line-height: 20px;
  font-weight: 600;
}
.ce__list > li { display: inline-flex; align-items: center; gap: $sp-2; }
.ce__list > li[hidden] { display: none; }
// 구분자는 앞 칸이 있을 때만 — 뒤 칸을 숨겨도 꼬리 구분자가 남지 않는다
.ce__list > li + li::before {
  content: "\203A";
  display: inline-flex;
  justify-content: center;
  width: 8px;
  color: rgba($color, .45);
}

a.ce__crumb { color: rgba($color, .72); text-decoration: none; border-radius: $r-xs; cursor: pointer; }
a.ce__crumb:hover { color: $color; text-decoration: underline; text-underline-offset: 4px; }
a.ce__crumb:focus-visible { outline: 2px solid $color; outline-offset: 2px; }

// 현재 칸: 굵기 + 진짜 밑줄 + 그 아래로 자라는 강조 막대
.ce__list .ce__cur {
  position: relative;
  color: $color;
  font-weight: 800;
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 2px;
}
.ce__list .ce__cur::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -8px;
  height: 4px;
  border-radius: $r-pill;
  background: $color;
  transform: scaleX(1);
  transform-origin: left center; // 규칙8: 현재칸 강조막대 좌측 성장
  transition: transform $duration $easing;
}

// 읽어 주는 말 — 실제로 aria-live 영역이다
.ce__say {
  display: inline-flex;
  align-items: center;
  gap: $sp-2;
  margin: 0;
  padding: $sp-2 $sp-3;
  border-radius: $r-pill;
  background: $subject-ink;
  color: $subject-cream;
  font-size: 12px;
  line-height: 16px;
  font-weight: 700;
  white-space: nowrap;
}
.ce__say svg { flex: none; color: $subject-cream; }
.ce__val { color: $subject-cream; }

// ── 자동 루프: 막대가 scaleX 로 자라고 말풍선이 떠오름 → 유지 → 접힘. 복귀는 88% 안에 ──
.ce.is-demo .ce__cur::after {
  animation-name: ce-bar;
  animation-duration: $dur-loop;
  animation-timing-function: $easing;
  animation-iteration-count: infinite;
}
@keyframes ce-bar {
  0%, 8%    { transform: scaleX(0); }
  42%, 76%  { transform: scaleX(1); }
  88%, 100% { transform: scaleX(0); }
}
// 말풍선은 나타남/사라짐만 steps(1, end) 로 컷하고 떠오름은 translateY 가 맡는다 —
// opacity 를 서서히 올리면 poster 가 반투명하게 뜬 흐린 알약이 된다 (blog-demo 실패표)
.ce.is-demo .ce__say {
  animation-name: ce-cut, ce-rise;
  animation-duration: $dur-loop, $dur-loop;
  animation-timing-function: steps(1, end), $easing;
  animation-iteration-count: infinite, infinite;
}
// 들어올 때만 컷(steps), 나갈 때는 서서히 — 나감도 컷하면 그 프레임이 가장 크게 달라져서
// poster 가 "말풍선이 사라진 빈 화면" 으로 뽑힌다 (demo.py 산출() 은 최대 변화 프레임을 고른다)
@keyframes ce-cut {
  0%        { opacity: 0; animation-timing-function: steps(1, end); }
  30%       { opacity: 1; animation-timing-function: linear; }
  76%       { opacity: 1; }
  88%, 100% { opacity: 0; }
}
@keyframes ce-rise {
  0%, 30%   { transform: translateY(6px); }
  52%, 76%  { transform: translateY(0); }
  88%, 100% { transform: translateY(6px); }
}

@media (max-width: 340px) {
  .ce { gap: $sp-5; }
  .ce__say { padding: $sp-1 $sp-2; font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  .ce.is-demo .ce__cur::after,
  .ce.is-demo .ce__say { animation: none !important; }
  .ce__list .ce__cur::after { transition: none; transform: scaleX(1); }
  .ce__say { opacity: 1; transform: none; }
}

@charset "UTF-8";
html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.ce {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  user-select: none;
  -webkit-user-select: none;
}

.ce__list {
  display: flex;
  align-items: center;
  flex-wrap: nowrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  white-space: nowrap;
  font-size: clamp(11px, 3.2vw, 14px);
  line-height: 20px;
  font-weight: 600;
}

.ce__list > li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.ce__list > li[hidden] {
  display: none;
}

.ce__list > li + li::before {
  content: "›";
  display: inline-flex;
  justify-content: center;
  width: 8px;
  color: rgba(23, 20, 26, 0.45);
}

a.ce__crumb {
  color: rgba(23, 20, 26, 0.72);
  text-decoration: none;
  border-radius: 4px;
  cursor: pointer;
}

a.ce__crumb:hover {
  color: #17141a;
  text-decoration: underline;
  text-underline-offset: 4px;
}

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

.ce__list .ce__cur {
  position: relative;
  color: #17141a;
  font-weight: 800;
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 2px;
}

.ce__list .ce__cur::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -8px;
  height: 4px;
  border-radius: 999px;
  background: #17141a;
  transform: scaleX(1);
  transform-origin: left center;
  transition: transform 600ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.ce__say {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 8px 12px;
  border-radius: 999px;
  background: #17141a;
  color: #fff7e6;
  font-size: 12px;
  line-height: 16px;
  font-weight: 700;
  white-space: nowrap;
}

.ce__say svg {
  flex: none;
  color: #fff7e6;
}

.ce__val {
  color: #fff7e6;
}

.ce.is-demo .ce__cur::after {
  animation-name: ce-bar;
  animation-duration: 2s;
  animation-timing-function: cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: infinite;
}

@keyframes ce-bar {
  0%, 8% {
    transform: scaleX(0);
  }
  42%, 76% {
    transform: scaleX(1);
  }
  88%, 100% {
    transform: scaleX(0);
  }
}
.ce.is-demo .ce__say {
  animation-name: ce-cut, ce-rise;
  animation-duration: 2s, 2s;
  animation-timing-function: steps(1, end), cubic-bezier(0.2, 0.8, 0.2, 1);
  animation-iteration-count: infinite, infinite;
}

@keyframes ce-cut {
  0% {
    opacity: 0;
    animation-timing-function: steps(1, end);
  }
  30% {
    opacity: 1;
    animation-timing-function: linear;
  }
  76% {
    opacity: 1;
  }
  88%, 100% {
    opacity: 0;
  }
}
@keyframes ce-rise {
  0%, 30% {
    transform: translateY(6px);
  }
  52%, 76% {
    transform: translateY(0);
  }
  88%, 100% {
    transform: translateY(6px);
  }
}
@media (max-width: 340px) {
  .ce {
    gap: 20px;
  }
  .ce__say {
    padding: 4px 8px;
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ce.is-demo .ce__cur::after,
  .ce.is-demo .ce__say {
    animation: none !important;
  }
  .ce__list .ce__cur::after {
    transition: none;
    transform: scaleX(1);
  }
  .ce__say {
    opacity: 1;
    transform: none;
  }
}

// 실동작: 앞쪽 칸을 누르면 그 칸이 현재 페이지가 된다 — aria-current 를 옮기고 뒤 칸을 숨긴다.
// 현재 칸을 한 번 더 누르면 전체 경로로 되돌린다. 링크라 Enter 로도 같은 동작.
var root = document.querySelector('.ce');
var lis = [].slice.call(document.querySelectorAll('.ce__list > li'));
var crumbs = lis.map(function (li) { return li.querySelector('.ce__crumb'); });
var val = document.querySelector('.ce__val');
var currentIndex = crumbs.length - 1;
function setCurrent(i) {
  root.classList.remove('is-demo');
  currentIndex = i;
  lis.forEach(function (li, n) {
    li.hidden = n > i;
    var c = crumbs[n];
    c.classList.toggle('ce__cur', n === i);
    if (n === i) c.setAttribute('aria-current', 'page');
    else c.removeAttribute('aria-current');
  });
  val.textContent = crumbs[i].textContent;
}
crumbs.forEach(function (c, i) {
  if (c.tagName !== 'A') return;
  c.addEventListener('click', function (e) {
    e.preventDefault();
    setCurrent(currentIndex === i ? crumbs.length - 1 : i);
  });
});

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

export type CurrentPageEmphasisProps = {
  trail?: string[];
  label?: string;
  duration?: number;
  easing?: string;
  color?: string;
};

type ClickEvt = { preventDefault(): void };
type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };

const IconCheck = () => (
  <svg viewBox="0 0 256 256" width="14" height="14" aria-hidden="true"><g fill="currentColor"><path d="M224 128a96 96 0 1 1-96-96a96 96 0 0 1 96 96" opacity=".2"/><path d="M173.66 98.34a8 8 0 0 1 0 11.32l-56 56a8 8 0 0 1-11.32 0l-24-24a8 8 0 0 1 11.32-11.32L112 148.69l50.34-50.35a8 8 0 0 1 11.32 0M232 128A104 104 0 1 1 128 24a104.11 104.11 0 0 1 104 104m-16 0a88 88 0 1 0-88 88a88.1 88.1 0 0 0 88-88"/></g></svg>
);

export default function CurrentPageEmphasis({
  trail = ["Home", "Electronics", "Laptops", "13-inch gaming"],
  label = "Current page",
  duration = 600,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#17141a",
}: CurrentPageEmphasisProps) {
  const [at, setAt] = useState(trail.length - 1);
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color };

  function pick(e: ClickEvt, i: number) {
    e.preventDefault();
    setAt(at === i ? trail.length - 1 : i);
  }

  return (
    <div className={styles.ce} style={vars}>
      <nav aria-label="Breadcrumb">
        <ol className={styles.list}>
          {trail.map((text, i) => (
            <li key={text} hidden={i > at}>
              {i === trail.length - 1
                ? <span className={[styles.crumb, i === at ? styles.cur : ""].join(" ")} aria-current={i === at ? "page" : undefined}>{text}</span>
                : <a
                    className={[styles.crumb, i === at ? styles.cur : ""].join(" ")}
                    href="#"
                    aria-current={i === at ? "page" : undefined}
                    onClick={(e: ClickEvt): void => pick(e, i)}
                  >{text}</a>}
            </li>
          ))}
        </ol>
      </nav>
      <p className={styles.say} aria-live="polite">
        <IconCheck /><span>{label}</span> · <span className={styles.val}>{trail[at]}</span>
      </p>
    </div>
  );
}