パンくずリスト

<%# Markup for the breadcrumb demo.
    The APG structure (nav + ol + aria-current="page") lives in the markup; the
    library only handles the responsive behavior of collapsing middle items into a
    "…" disclosure button when width runs short. Separators are drawn by demo.css's
    ::after. aria-controls lists the id of *every* item the button collapses, so the
    control relationship is complete rather than pointing at the first one only.

    About the href values — this part is demo scaffolding, not a pattern to copy. A real
    breadcrumb links to real paths and wants Turbo to handle them; replace the hrefs and
    drop the data-turbo attribute when you copy this.

    A catalog demo has nowhere real to go, and the usual placeholder `href="#"` is worse
    than useless here: Turbo reads it as a visit to the current page, re-renders the body
    from the server's HTML, and the trail you just expanded snaps shut (then flashes open
    from the cached snapshot on the way back). Pointing at a same-page fragment only
    helps on the first press — once the URL carries that hash, the next press is a
    same-URL visit again and resets just the same, which is measurable in the browser.
    So the demo opts out of Turbo for this subtree (data-turbo is inherited, so one
    attribute covers every link): the browser then treats them as what they are, a scroll
    to an element in this document, and the controller's state is never torn down. %>
<div id="breadcrumb-demo" class="breadcrumb-demo" data-turbo="false">
  <%# The trail collapses only when it does not fit, so the demo needs a width it can
      lose. Widen it past the full trail and nothing collapses and nothing scrolls;
      narrow it and the middle items bank behind the "…". %>
  <label class="demo-width-control">
    <span><%= t("components.breadcrumb.demo.width") %></span>
    <input type="range" min="220" max="640" value="352" data-breadcrumb-demo-width>
  </label>

  <nav
    class="breadcrumb"
    data-controller="stimeo--breadcrumb"
    aria-label="<%= t("components.breadcrumb.demo.label") %>">
    <ol class="breadcrumb__list" data-stimeo--breadcrumb-target="list">
      <li class="breadcrumb__item">
        <a href="#breadcrumb-demo"><%= t("components.breadcrumb.demo.home") %></a>
      </li>
      <li class="breadcrumb__item" data-stimeo--breadcrumb-target="ellipsis" hidden>
        <button
          type="button"
          class="breadcrumb__ellipsis"
          aria-expanded="false"
          aria-controls="breadcrumb-collapsed-1 breadcrumb-collapsed-2 breadcrumb-collapsed-3"
          aria-label="<%= t("components.breadcrumb.demo.expand") %>"
          data-stimeo--breadcrumb-target="trigger"
          data-action="click->stimeo--breadcrumb#toggle">…</button>
      </li>
      <li
        class="breadcrumb__item"
        id="breadcrumb-collapsed-1"
        data-stimeo--breadcrumb-target="collapsible">
        <a href="#breadcrumb-demo"><%= t("components.breadcrumb.demo.section") %></a>
      </li>
      <li
        class="breadcrumb__item"
        id="breadcrumb-collapsed-2"
        data-stimeo--breadcrumb-target="collapsible">
        <a href="#breadcrumb-demo"><%= t("components.breadcrumb.demo.subsection") %></a>
      </li>
      <li
        class="breadcrumb__item"
        id="breadcrumb-collapsed-3"
        data-stimeo--breadcrumb-target="collapsible">
        <a href="#breadcrumb-demo"><%= t("components.breadcrumb.demo.category") %></a>
      </li>
      <li class="breadcrumb__item">
        <a href="#breadcrumb-demo" aria-current="page">
          <%= t("components.breadcrumb.demo.current") %>
        </a>
      </li>
    </ol>
  </nav>
</div>

/*
 * Presentation-only styles for the breadcrumb demo.
 * Collapse/expand is the library toggling the hidden attribute of collapsible items
 * and the ellipsis, plus the trigger's aria-expanded. Here we narrow the container
 * to force overflow and draw the "/" separator with ::after.
 */

.breadcrumb-demo {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

/* The width the slider drives. The declared value is the starting point and the
   fallback when the sidecar script is absent: narrow enough that the trail collapses,
   so the component's own behavior is what greets the reader.

   The frame is what makes the width legible — without it the container has no visible
   edge and the trail appears to shorten for no reason. The controller reads both widths
   off the list itself, so this padding does not skew its overflow check. */
.breadcrumb {
  max-width: 22rem;
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  overflow: hidden;
}

/* When the user expands the collapsed trail, let the row scroll instead of clipping it,
   so every item — including the current page — can be reached inside the container. It
   scrolls rather than spilling out: `overflow: visible` let the trail run past the edge
   of a narrow card (measured at ~529px out of a 200px card), which is not something a
   demo should be teaching. Only the inline axis is relaxed: the list stays nowrap so its
   measured width is unchanged, which avoids retriggering the controller's
   ResizeObserver-driven overflow check (wrapping it would make the trail re-collapse).
   The "…" button doubles as the re-collapse toggle, so it stays in place.

   Keyboard reach comes from the links inside the row, which are all in the tab order —
   a scroll container reachable only by pointer would fail WCAG 2.1.1. `scroll-padding`
   keeps the item a link scrolls into view clear of the sticky-feeling left edge. */
.breadcrumb:has([data-stimeo--breadcrumb-target="trigger"][aria-expanded="true"]) {
  overflow-x: auto;
  scroll-padding-inline: 0.25rem;
}

.breadcrumb__list {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: 0.25rem;
  margin: 0;
  padding: 0;
  list-style: none;
  white-space: nowrap;
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.875rem;
}

/* Collapsing is expressed purely through the hidden attribute, and the author-origin
   `display: inline-flex` above always beats the UA's `[hidden] { display: none }`
   (origin, not specificity — reordering or lowering specificity does not help). Restore
   it here so this file works on its own wherever it is pasted. */
.breadcrumb [hidden] {
  display: none !important;
}

.breadcrumb__item:not(:last-child)::after {
  content: "/";
  color: var(--color-text-subtle);
}

/* The theme-aware accent *text* token, not the raw brand accent: the latter measures
   2.86:1 on the light canvas (#0ea88f on #f8fafc), below the 4.5:1 floor for body-size
   text. Same substitution the rest of the catalog already carries. */
.breadcrumb__item a {
  color: var(--accent-700);
  text-decoration: none;
}

.breadcrumb__item a[aria-current="page"] {
  color: var(--fg, var(--color-text));
  font-weight: 600;
  pointer-events: none;
}

.breadcrumb__ellipsis {
  padding: 0 0.25rem;
  border: 0;
  background: none;
  color: var(--color-text-muted);
  font: inherit;
  line-height: 1;
  cursor: pointer;
}

.breadcrumb__ellipsis:hover {
  color: var(--fg, var(--color-text));
}

.breadcrumb__ellipsis:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

// Breadcrumb demo (consumer-side JS).
//
// The controller needs no knob of its own — it watches the trail with a ResizeObserver
// and collapses the middle items when they stop fitting. This slider only changes the
// width they have to fit into, so the threshold can be crossed in both directions:
// wide enough and the whole trail shows with no scrolling, narrow and it banks behind
// the "…".
document.querySelectorAll(".breadcrumb-demo").forEach((root) => {
  const trail = root.querySelector('[data-controller~="stimeo--breadcrumb"]');
  const range = root.querySelector("[data-breadcrumb-demo-width]");
  if (!trail || !range) return;

  const apply = () => {
    trail.style.maxWidth = `${range.value}px`;
  };
  apply();
  range.addEventListener("input", apply);
});