Looks great. I love the amount of effort you spent in CSS to make it look native. A couple feedback notes:

1. You might want to add the following to remove the Mobile Safari UI chrome when users add the app to the Home Screen:

<meta name="apple-mobile-web-app-capable" content="yes">

<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">

<link rel="apple-touch-startup-image" href="img/splash.png">

2. On the iPad, the clickable regions are a bit awkward. The external link takes up a good 95% of the menu item. The view comments link is (logically) the button, but it's too small relative to the importance of the discussion on HN.