Stylesheet not loaded on register page

You need login_enqueue_scripts for the login page.

See: https://codex.wordpress.org/Plugin_API/Action_Reference/login_enqueue_scripts

Swap that out in your add_action, or add a new one, and it should work.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)