wp_render_custom_css_support_styles( array $parsed_block ): array

29function wp_render_custom_css_support_styles( $parsed_block ) {30	$custom_css = $parsed_block['attrs']['style']['css'] ?? null;31	if ( ! is_string( $custom_css ) || '' === trim( $custom_css ) ) {32		return $parsed_block;33	}34 35	$block_type = WP_Block_Type_Registry::get_instance()->get_registered( $parsed_block['blockName'] );36	if ( ! block_has_support( $block_type, 'customCSS', true ) ) {37		return $parsed_block;38	}39 40	// Validate CSS doesn't contain HTML markup (same validation as global styles REST API).41	if ( preg_match( '#</?\w+#', $custom_css ) ) {42		return $parsed_block;43	}44 45	// Generate a unique class name for this block instance.46	$class_name          = wp_unique_id_from_values( $parsed_block, 'wp-custom-css-' );47	$existing_class_name = $parsed_block['attrs']['className'] ?? null;48	$updated_class_name  = is_string( $existing_class_name )49		? "$existing_class_name $class_name"50		: $class_name;51 52	_wp_array_set( $parsed_block, array( 'attrs', 'className' ), $updated_class_name );53 54	// Process the custom CSS using the same method as global styles.55	$selector      = '.' . $class_name;56	$processed_css = WP_Theme_JSON::process_blocks_custom_css( $custom_css, $selector );57 58	if ( ! empty( $processed_css ) ) {59		/*60		 * Register and add inline style for block custom CSS.61		 * The style depends on global-styles to ensure custom CSS loads after62		 * and can override global styles.63		 */64		wp_register_style( 'wp-block-custom-css', false, array( 'global-styles' ) );65		wp_add_inline_style( 'wp-block-custom-css', $processed_css );66	}67 68	return $parsed_block;69}