How to change Sign up page design in Moodle

I am new to moodle and i am using 2.9. I have a separate design for Signup page (HTML5 & CSS). How to integrate this page ? I know the process of changing the default Login page like this In config.php of my theme 'login' => array( 'file' => 'login.php', 'regions' => array(), 'options' => array('langmenu'=>true), ), Where my Custom login page is login.php which is placed in my layout folder. So in this way i can takeover Login page design with my new design. But i don't see any signup array in config page for Registration. So anyone can tell me how to do this change ? Edit - I have checked this file moodle2\login\index_form.html I can see the signup design. But my issue is that file index_form.html has Moodle core CSS if i add my CSS there it will conflict also i dont know how to load the CSS from my theme folder to index_form.html. Can anyone guide me ? I already checked Moodle.org forum but not able to find the process. Thanks In Advance Lorry