I'm already getting congratulations on such a nice-looking UI, but I don't deserve it. The credit should go to Twitter for releasing the Bootstrap toolkit, which I have been learning and building on.
I needed a framework of solved problems that I could hook into. Trying to put all the pieces together when I'm already managing a billion pieces in my own world was going to take forever. They just put out a set of easy UI techniques that I could hook into. From there, it was mostly just programming. The complexities melted away.
This has been the problem with CSS. It was designed for laying out documents, for apps we need something akin to the Mac Toolkit (they call it Cocoa these days, I think). I'm not sure Twitter realized they were developing that, but they gave a guy like me what I needed to put it together.
They aren't the first, but I've spent a fair amount of time staring at other UI toolkits and never got to Hello World. With this one, once I realized the answers were available by doing a View Source, it was off to the races.
Update: Here's a set of Bootstrap demos. They make it easier to get started.