Stacks provides everything you need to quickly design, build, and ship coherent experiences across all of Stack Overflow—from the brand and product itself, down to how we send emails and write copy.

Product Robust CSS & JavaScript Pattern libraries for rapidly building Stack Overflow.
Email Patterns and guidelines for creating and sending emails to Stack Overflow users.
Content Principles and tactics for writing at Stack Overflow.
Brand Visual patterns and guidelines for Stack Overflow’s brand.