CSS overrides are nice but sometimes you need to alter your submit button to show up the same way in all browsers (yes, you IE!).
Even though installing Domain Access allows to manage content on multiple domains it does not require multiple site folders and settings.php files. There is only one central settings.php file for the default domain. For Domain Access to work, you must add some code to your settings.php file. This code will load the Domain Access bootstrap routines that determine how your site is being requested.
Installing Domain Access on Dreamhost