Which design principle is primarily focused on user experience?

User-centered design is a design principle primarily focused on user experience because it emphasizes understanding the needs, preferences, and behaviors of the users throughout the design process. This approach prioritizes the end-user's interaction with the product, ensuring that the design is intuitive, accessible, and user-friendly.

In user-centered design, the goal is to create solutions that resonate with users, making their experience enjoyable and efficient. This involves researching users, iterating on designs based on feedback, and testing prototypes to align the final product with user expectations.

Other design principles, such as symmetry, contrast, and balance, do contribute to the aesthetic and functional quality of a design but do not inherently focus on the user's experience. Symmetry relates to visual harmony, contrast deals with the differentiation of elements for visibility and emphasis, and balance refers to the distribution of visual weight in a design. While these principles are essential in creating effective designs, they are not as directly connected to enhancing user experience as user-centered design is.