Ask HN: What resource is the best for learning modern CSS and design techniques?

I've done CSS, HTML, ASP, and PHP in the past, but I've definitely fallen behind the times. When I go to design websites, I constantly find myself checking w3c to see what I can/can't do, and even when I finish websites, they have a decidedly 2000s look to them.

So, my questions are...

1. What's a good book (not just a reference) to learn modern CSS design, techniques, and good style?

2. What else should I be looking into besides CSS, if anything, to bring myself up to date?

Thanks.