QuickTickets Dashboard Theme's background Colour

i’m using the Qucktickets Dashboard Theme. I have modified the theme according to my requirement. But i’m unable to change the background color of the first login page. Instead of dark color i need blue. How to do? Please help…

The theme seems to use selector “.dashboard .login-bg” to style the background of the login page. You should overwrite or modify the background styles of that selector.

Thanks You!!!