Most of the wireframes and example in this book pertain to desktops sized design. But the design principles and methodologies are device agnostic. It’s all about the research. We have found that design for smaller screen is all about the priorities. With a desktop screen you put the important things front and center and you often use large images to tell a rich, compelling story. This doesn’t work so well on mobile, where you might have a much smaller viewport and slow download times. You can’t show primary content supported by secondary content in (for example) a right column. You need to get your message across in just a few pixels.