add theme suggestions

gistfile1.txt

/**
 * Implements hook_theme_suggestions_HOOK_alter() for block templates.
 */
function custom_theme_suggestions_node_alter(array &$suggestions, array $variables) {
  $element = $variables['elements'];
  // Add template suggestions based on the current view mode.
  $node = $variables['elements']['#node'];
  $suggestions[] = 'node__' . $variables['elements']['#view_mode'];
  $suggestions[] = 'node__' . $node->bundle() . '__' . $variables['elements']['#view_mode'];
}

/**
 * Implements hook_theme_suggestions_HOOK_alter() for block templates.
 */
function custom_theme_suggestions_field_alter(array &$suggestions, array $variables) {
  $element = $variables['element'];
  // Add template suggestions based on the current view mode.
  $field_name = $variables['element']['#field_name'];
  $suggestions[] = 'field__' . $variables['element']['#view_mode'];
  $suggestions[] = 'field__' . $field_name . '__' . $variables['element']['#view_mode'];
}

/**
 * Implements hook_theme_suggestions_HOOK_alter() for block templates.
 */
function custom_theme_suggestions_block_alter(array &$suggestions, array $variables) {
  if (isset($variables['elements']['content']['#block_content'])) {
    $suggestions[] = 'block__' . $variables['elements']['content']['#block_content']->bundle();
  }
}