Implements hook_preprocess_node() for paragraph node templates.
Attach css we need for paragraph demo content.
function paragraphs_demo_preprocess_node(&$variables) {
// If more general approach is needed then implement preprocessor for
// paragraph.html.twig.
if ($variables['node']
->getType() === 'paragraphed_content_demo') {
$variables['#attached']['library'][] = 'paragraphs_demo/drupal.paragraphs_demo';
}
}