A list of things to read or watch that address these two questions: What is scalable CSS? and How do we create scalable CSS?
By scalable CSS, I mean CSS that is - capable of remaining effective, coherent, extendable, and maintainable as projects grow over time - capable of being understood and worked on by any number of different people in a consistent, systematic way
Included are resources that articulate key principles and practices. The list is restricted to the articles that I consider the most important to read – that is, the best explanations (of which I’m aware) for different approaches to the problems.
If you know of a resource that should be added, please share! File an issue or a pull request.
(There are plenty of other problems related to CSS: understanding how it works, using specific properties, accomplishing specific styles, achieving responsive design, boosting performance, etc. This list is strictly focused on the problem of creating scalable CSS.)
None of the sections present any kind of “ranking” or “suggested reading order.” Just read them all.
Newest on top, oldest on bottom. (A note for you outside the US: my dates are month/day/year format.)
These styleguides articulate conventions and guidelines for authoring scalable CSS.
(I’m distinguishing styleguides from what I would call pattern libraries, which are references created to document and exemplify existing styles rather than guidelines for the authoring of the styles. Other people often use the term styleguide to refer to both or either of these reference types. I think pattern libraries are less specifically about scalable CSS, and more about a scalable frontend design and development workflow; so I’m not including resources related to pattern libraries.)
How we do CSS at [blank] …
Articles providing overviews of real-life CSS methodologies for production sites and apps of significant scale. Although these articles generally don’t include principles that are not better explained in the articles and longer reads above, they are so pragmatic and concrete that they are important reads in their own right. Newest first.
Newest first, I think.