What does the term "responsive design" refer to?

Responsive design refers to the ability of a design to adjust to different screen sizes and orientations, ensuring an optimal viewing experience across a wide range of devices, from desktops to smartphones. This approach involves fluid grids, flexible images, and CSS media queries that allow web layouts to adapt seamlessly to the user's screen.

The focus on responsiveness is essential because users access content on various devices, and a consistent user experience enhances usability and engagement. By implementing responsive design principles, designers can create interfaces that work well regardless of resolution, leading to higher user satisfaction.

Other options do not align with the definition of responsive design. Designing only for mobile does not consider users on tablets or desktops, fixed layouts restrict the adaptability of a design, and ignoring user interface principles would lead to ineffective design that fails to cater to user needs.