This Style Guide is a comprehensive resource for designing schematic symbols, PCB footprints, and 3D models used in printed circuit board (PCB) design. Its primary goal is to standardize the library design process across projects, and teams, and eventually influence CAD tools industry-wide, enabling seamless interoperability of CAD files. In addition to promoting consistency, the guide offers flexibility, allowing designers to choose between recommended land patterns, IPC standards, or a combination of both. Drawing on years of experience and industry best practices, the Style Guide aspires to be the definitive standard for library design, promoting high-quality, accurate, and standardized output.