As GrandMasterB mentioned, the current trend is to use scaffolding and responsive column-based layouts that make it much easier to write web applications for multiple target environments all at the same time: PCs, tablets, smartphones.
The most used is Twitter's Bootstrap... to the point where you can almost instantly recognize a website using it. To the point where a blog post has been written to stop using it... And as such, a lot of websites with Bootstrap themes (free or/and premium) have popped out of nowhere such as Bootswatch for example.
I don't know if this trend is going to stop or if it will fall into "another way of writing web apps", but there are many pros while working with such frameworks:
- Part of the responsive design is already done for you (and if you don't do too much complicated stuff, that part is going to be very close to 100%)
- It's easy to pick up (for exmaple: most important CSS classes in Bootstrap:
spanx where x is a number between 1 and 12)
- It's easily customizable with additional fonts, icons, theme colors
- It's pretty !
- You save a lot of time for more important stuff rather than micro-managing pixel by pixel all your DOM elements (you can still do that, sure, but if you do things well, you should not have to)
- They come with JQuery-based components
- It's still being worked on, and updated with modern CSS3 and HTML5 features while keeping compatibility with older browsers
- It's incredibly easy to integrate Bootstrap to a MVVM framework such as KnockoutJS for example.
And last but not least... Both Bootstrap and Zurb Foundation have excellent documentations
Edit: found a website comparing Bootstrap to Zurb Foundation and to another one that I didn't knew of, Skeleton (still grid/column based): http://responsive.vermilion.com/compare.php