I would want to modify the sidebar section.

I would like to do the following modifications in sidebar, kindly assist:

1. Increase the font size of the sidebar. Make it similar to the body font which I have changed to 20 px.
2. Change links, links hover, and visited link color only on the sidebar.
3. Add a separator line between widgets. For example separate RECENT POSTS with CATEGORIES
4. Add background to the title of the widgets. For example, RECENT POSTS.

The page I need help with: [log in to see the link]