Need to make some changes

Hello, first of all, I’d like to say how good your these is. It suits what I need absolutely perfectly.

I do however, need to make some small changes. I’d like to change the following, but cant figure out what lines on the stylesheet to change.

Default text size in posts.
Default colour in posts.

Default colour in post preview on my front page.

Which lines are these on please?

Regards

Gerry