Initial Drupal 11 with DDEV setup

web/core/themes/stable9/stable9.theme

@@ -0,0 +1,34 @@
+<?php
+
+/**
+ * @file
+ * Functions to support theming in the Stable9 theme.
+ */
+
+/**
+ * Implements hook_preprocess_item_list__search_results().
+ *
+ * Converts the markup of #empty for search results.
+ */
+function stable9_preprocess_item_list__search_results(&$variables): void {
+  if (isset($variables['empty']['#tag'])) {
+    $variables['empty']['#tag'] = 'h3';
+  }
+}
+
+/**
+ * Implements hook_preprocess_views_view().
+ *
+ * Adds BC classes that were previously added by the Views module.
+ */
+function stable9_preprocess_views_view(&$variables): void {
+  if (!empty($variables['attributes']['class'])) {
+    $bc_classes = preg_replace('/[^a-zA-Z0-9- ]/', '-', $variables['attributes']['class']);
+    $variables['attributes']['class'] = array_merge($variables['attributes']['class'], $bc_classes);
+  }
+  if (!empty($variables['css_class'])) {
+    $existing_classes = explode(' ', $variables['css_class']);
+    $bc_classes = preg_replace('/[^a-zA-Z0-9- ]/', '-', $existing_classes);
+    $variables['css_class'] = implode(' ', array_merge($existing_classes, $bc_classes));
+  }
+}