[Login Page] Remove standard style

hey guys,
I’ve got a question. How can I remove the wp-admin.css and colors-fresh.css from the wp-login page?

I have tried:
wp_deregister_style( ‘wp-admin-css’ );
wp_deregister_style( ‘colors-fresh-css’ );

and

wp_dequeue_style( ‘wp-admin-css’ );
wp_dequeue_style( ‘colors-fresh-css’ );

but not working ??

Thanks