Product design and development can cover a range of devices and platforms: iPhone, iPad, Android phones and tablets, responsive web applications and web sites, desktop apps… and if you work in a very large organization, you may have a range of products and features within each of these areas. In order to stay productive and effective across teams, platforms, and/or devices, systemic design and development is imperative. Style Guides are a great step towards keeping everything aligned. But how can the style guide be a maintainable, useful resource rather than a distraction? Learn from a product designer's perspective from past and current projects how she and her teams have strived to maintain a "single source of truth" for a truly living spec through a living style guide and prototype — all of which can improve your product design and development lifecycle.