How add dynamic css in WP plugin while rendering shortcode

wp-dynamic-css.php

function render_shortcode_template($atts){

		extract(shortcode_atts(array(), $atts));
	
		if($this -> get_option("_show_icons") == 'yes'){
			wp_enqueue_style('font-awesome', '//maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css');
		}
		
		wp_enqueue_style($this->plugin_meta['shortname'].'-styles', $this->plugin_meta['url'].'templates/post-frontend-style.css');
		//getting dynamic css
		ob_start();
		$this -> load_template('dynamic-css.php');
		$output_css = ob_get_contents();
		ob_end_clean();
		wp_add_inline_style( $this->plugin_meta['shortname'].'-styles', $output_css );
		wp_add_inline_style( $this->plugin_meta['shortname'].'-styles', $this -> get_option("_custom_styles") );
		
		
		if ( is_user_logged_in()) {

			ob_start();
			
			$this -> load_template('post-frontend-form.php');
			$output_string = ob_get_contents();
			ob_end_clean();
				
			return $output_string;
		}else{
			
			echo '<script type="text/javascript">
			window.location = "'.wp_login_url( get_permalink() ).'"
			</script>';
		}
		
	}