private function has_custom_css() {
		$query = new \WP_Query(
			array(
				'post_type'              => 'custom_css',
				'post_status'            => 'publish',
				'numberposts'            => 1,
				'update_post_meta_cache' => false,
				'update_post_term_cache' => false,
			)
		);

		if ( $query->have_posts() ) {
			$query->the_post();
			$content = get_the_content();

			// if the content contains a colon, a CSS rule has been added.
			return strpos( $content, ':' ) === false ? false : true;
		}

		return false;
	}