p5systems, I'm sorry, I'm not quite understanding your answer because I'm still learning my way around WP.
For example, I want three different Portfolio pages: Video, Photography, and Ebooks. Video portfolio is for category "videos," Photography portfolio is for category "photos," and Ebooks portfolio is for category "books." Let's say portfolio page for video is ID #123, for photography it is ID #456, and for ebooks it is ID #789.
How would I modify your code example for the Video portfolio page? If I see how it's done for a specific page and parameters, then the other two would be easy to figure out.
Also, do I insert the code into the Custom CSS in Theme Options, or do I insert it elsewhere, perhaps a child theme?
Pinboard is a great theme, and I'd love to be able to customize it just a little bit more. Thank you :)