ローカル時刻表示

<%# Markup for the local-time demo.
    Each <time> carries a machine-readable UTC datetime; the controller reformats the
    visible text into the viewer's locale and timezone via Intl.DateTimeFormat, leaving
    the datetime attribute (the screen-reader / SEO value) intact. The locale follows the
    page language and the timezone follows the browser, so the server can emit plain UTC
    and stay cacheable. The last row clears the time style to show a date-only format. %>
<% rows = [
     { at: Time.utc(2026, 6, 8, 12, 30), key: "published", date: "medium", time: "short" },
     { at: Time.utc(2026, 1, 1, 9, 0), key: "released", date: "full", time: "short" },
     { at: Time.utc(2026, 12, 24, 21, 0), key: "starts", date: "long", time: "" },
     { at: Time.now.utc, key: "now", date: "medium", time: "medium" }
   ] %>
<ul class="local-time-demo">
  <% rows.each do |row| %>
    <li class="local-time-demo__row">
      <span class="local-time-demo__label">
        <%= t("components.local_time.demo.#{row[:key]}") %>
      </span>
      <span class="local-time-demo__convert">
        <span class="local-time-demo__source">UTC <%= row[:at].strftime("%Y-%m-%d %H:%M") %></span>
        <span class="local-time-demo__arrow" aria-hidden="true">→</span>
        <time
          class="local-time"
          data-controller="stimeo--local-time"
          datetime="<%= row[:at].iso8601 %>"
          data-stimeo--local-time-locale-value="<%= I18n.locale %>"
          data-stimeo--local-time-date-style-value="<%= row[:date] %>"
          data-stimeo--local-time-time-style-value="<%= row[:time] %>"
          data-stimeo--local-time-title-format-value="long">
          <%= row[:at].strftime("%Y-%m-%d %H:%M UTC") %>
        </time>
      </span>
    </li>
  <% end %>
</ul>
<p class="local-time-demo__hint"><%= t("components.local_time.demo.hint") %></p>

/*
 * Presentation-only styles for the local-time demo.
 * The library only replaces the element's text with the localized absolute time
 * (and adds a detailed title); the machine-readable datetime attribute is kept.
 */

.local-time-demo {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  max-width: 46rem;
}

.local-time-demo__row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  /* Keep the label and value on one line when there's room; on a genuinely narrow
     stage the value group drops to a second line as a whole — never mid-value
     (see the nowrap rules below), which is what made English look cluttered. */
  flex-wrap: wrap;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 0.375rem;
}

.local-time-demo__label {
  color: var(--muted);
  font-size: 0.9rem;
}

.local-time-demo__convert {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  white-space: nowrap;
}

/* The source UTC, shown next to the localized time so the conversion is verifiable. */
.local-time-demo__source {
  color: var(--muted);
  font-size: 0.8rem;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.local-time-demo__arrow {
  color: var(--muted);
}

/* The localized absolute time. An English full date is long, so keep it on one
   line and let the row (not the time) wrap when space is tight. */
.local-time {
  font-variant-numeric: tabular-nums;
  color: var(--fg);
  white-space: nowrap;
}

/* Explanatory caption: the time is localized on the client from the UTC datetime. */
.local-time-demo__hint {
  margin: 0.75rem 0 0;
  max-width: 46rem;
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--muted);
}