Network theme menu shows a gray box when on that page and I want to change the color.

There aren't any options for changing the background color on the menu item when you are ON the page that's listed. It's an ugly gray color and I want to change it. How do I do that? Can you also please tell me how to change the teal color (teal.css) to another color. I tried looking in the Editor but can't find the file, nor can I find a custom CSS editor.

Also, I tried the Social Theme and the blogs looked like posts... which would be fine except I want a regular blog site with the social network showing the newest posts like facebook does in the newsfeed with statuses. Is there anyway to change the appearance of the blog?