Can you use CSS style attributes in Report Builder 2.0?

Yes, only a few CSS attributes are allowed. You directly use the attribute from a list of options for the property in the Expression.

Alignment, Padding, font related items etc are all set using their attributes.

For example:
The Text "Total" has been replaced by the one shown in the figure using the following for the CSS attributes:

Font: Verdana to Jokerman
Font-size: 9pt to 16pt
Alignment: Default to Center
Fill: #920202 to Dark Violet