Added subnavbar.

Pages/Bits/SubNavbar.php

@@ -0,0 +1,39 @@
+<?php
+
+$SubNavbarItems ??= [];
+
+if (count($SubNavbarItems) === 0) {
+    return;
+}
+
+$SubNavbarCurrent ??= null;
+
+?>
+
+<nav
+    class="SubNavbar"
+    aria-label="Secondary navigation"
+>
+    <?php foreach (
+        $SubNavbarItems
+        as $SubNavbarName => $SubNavbarHref
+    ): ?>
+        <a
+            class="SubNavbarLink"
+            href="<?= htmlspecialchars(
+                $SubNavbarHref,
+                ENT_QUOTES,
+                "UTF-8"
+            ) ?>"
+            <?= $SubNavbarCurrent === $SubNavbarName
+                ? 'aria-current="page"'
+                : "" ?>
+        >
+            <?= htmlspecialchars(
+                $SubNavbarName,
+                ENT_QUOTES,
+                "UTF-8"
+            ) ?>
+        </a>
+    <?php endforeach; ?>
+</nav>