CSS control of links in sidebar

Hi
I’m setting up a new site and blog, and have been trying to link the blog to my CSS. In order to keep things tidy I’m using an override CSS that only the blog looks at (via the header).

I’m trying to customize the fonts and links in the sidebar div, but can’t seem to control them. For instance, I saw something on the support page for wp_get_pages that refers to CSS classes .page_item and .current_page_item, but can’t get these to work.

Any suggestions?