Fitbit had exponential growth in its first decade as a business. Along with, its e-commerce website had to develop fast to meet business demands, and this created some design inconsistencies. As the in-house team prepared to update the global website, I joined the team to help prepare the transition into a modular design system. We began by developing a web style guide, which catalogued and organized new and existing design elements. Then, we applied these principles to the redesign of the cart and check out experience, setting the groundwork for a responsive design thinking process.