I tried to view your css file, and it says that there is a server misconfiguration.
I might know what your problem is.
When i first started with CPanel it took me a while to figure this one out too.
Go to Mysql Databases in cpanel. go to Add Users to Your Databases.
Click the drop down for your user, and then one for your DB, then make sure that all is checked, and then click add user to Database. This should allow your username to access the database.
With Cpanel it is not always spelled out clearly (even though it is one of the best backend programs) how to do things. Post again if this doesnt solve the problem.
