What defines a box layout in web design?

A box layout in web design is characterized by the use of boxes or squares that can vary in sizes and proportions to create a visually appealing and organized structure. This approach allows for a flexible design that can adapt to different types of content, ensuring that each box can be sized appropriately to fit its content while maintaining an overall aesthetic balance.

This design methodology often employs aspects of the grid system, giving designers the ability to create a hierarchical layout that guides the user's eye through the content effectively. The use of varying sizes also facilitates the highlighting of important elements, making the layout more engaging and dynamic.

The other options, while touching on elements of web design, do not encapsulate the essence of a box layout as accurately. Uniform sizes would suggest a rigid structure, multiple columns of text do not necessarily imply a box layout on their own, and using boxes solely for navigation would limit the versatility that a box layout can offer.