A nicely-documented styleguide from Atlassian. It’s not a component library, though—there’s no code here.
An in-depth look at the current Shadow DOM spec. It’s well-written but I don’t think this will really click with me until I start playing around with it for myself.
It’s good to see that the examples have some thought given to fallback content.
There’s also a corresponding tutorial on custom elements
I think Tyler’s onto something here:
I noticed three qualities that recurred in different combinations. Without at least two, the projects seemed doomed to failure.
I certainly think there’s a difference in how you approach a pattern library intended as a deliverable (something we do a lot of at Clearleft) compared to building a pattern library for an ongoing ever-evolving product.
If you don’t comment your CSS, you’ll confuse other people looking at your code, and, more embarrassingly, you’ll confuse future you. If you do comment CSS, everybody will be less confused, and things will be accidentally broken less often. You will be popular and generally well-liked, and people will remember to send you cards on your birthday. Comment more.
Some good advice here on how to write better comments in CSS.
A pattern library of Walmart’s front-end code.
A nicely documented pattern library.
A nice combination of style guide and pattern library, with plenty of documentation.
Mark Otto talks through the state of Github’s CSS and the processes behind updating it. There’s a nice mix of pragmatism and best practices, together with a recognition that there’s always room for improvement.
A handy one-stop-shop for documentation on web technologies.
Jason goes into detail describing the File Format problem that he and others are going to tackle in the effort known as Just Solve The Problem.
Put this one on speed dial.
A beautifully readable subset of the HTML spec, with an emphasis on writing web apps (and with information intended for browser makers has been removed). Very handy indeed!
Hixie needs your help. Document examples of augmented video (or audio) such as captioned or subtitled media.
A very handy interface for browsing the contents of the HTML5 spec.
A nice way to play around with Google's APIs. Example code is provided which you can edit and immediately see the results.