Different style for different page template

Hi there, I want to apply different sidebar style on full width page template, I created this in functions.php:

function diffrent_style(){
   wp_enqueue_style('pup-slider',get_template_directory_uri().'css/pup-slider.css');
}

and in full-width.php:

add_action('wp_enqueue_scripts', 'diffrent_style');

But it doesn’t affect anything, what’s the problem?