Excellent. From a usability standpoint, please design a blank state for the content area on desktop, it is not clear at the moment. @publicfig "EDIT: I would honestly like to see this scale on desktop, just because it's a pretty great interface for Hacker News. " also backs this up.

How? Instead of the orange, make it light, and add label + icon, (like in Mail.app) to show nothing is selected. Just my 2c.