Widgets not automatically styled like theme in update

Since I updated to Atahualpa 3.6.4, I find that links, etc. are not styled in widgets the same way they are in the rest of the theme.

I've had to go in and set the CSS for the widgets so that the look there matched the rest of the site.

Is there a reason that it is better or necessary for 3.6.4 to be this way as opposed to the way it used to be?

Thanks.