This course introduces the approach of mobile-first design in building responsive websites, prioritizing optimization for smaller screens and then scaling up to larger screens using CSS Grid. It focuses on the principles of responsive web design, emphasizing the use of media queries and the CSS Grid layout module to create complex and flexible layouts that adapt to the screen sizes of various devices. The course guides learners through setting up a CSS Grid-based layout that starts with the mobile viewpoint as the default styling. Then, it progressively enhances the user experience with additional features and layouts for tablets and desktops. Participants learn to leverage the power of CSS Grid to manage both columns and rows, align content, and build intricate designs that maintain their integrity across different devices. The aim is to equip learners with the skills needed to deliver an optimal viewing experience that is consistent, accessible, and user-friendly, starting from the smallest device.