tablet friendly website, responsive design, css3

my website is now tablet friendly. More specifically, in portrait mode, the side bar doesn't show.
here's a sample page. 〈Xah CSS Tutorial〉 http://xahlee.info/js/css_index.html

for this to happen, it's very simple. See:
〈CSS: Media Query (Responsive Design)〉

however, took me about 5 hours. Why O Why? that's how things are. We are not talking about old browsers or Internet Explorer 8. I'm designing only for “real modern” browsers. But, still, the pain won't go away. Why my paragraph width got shrinked on this modern Motorola Xoom super Android cynogenmod browser? Then, download Google Chrome browser, seems to work there. Then, try to find a way to determine just what browser is that one running in cynogenmod. Then, try CSS variations, then, try to read the spec. Then, try CSS variations, then, try to read the spec, more carefully. Then, rub ya gloss. Then, rub ya eyes. Why O Why this isn't expect. You know what i mean?