Which layout is CSS Grid primarily designed for?

CSS Grid is primarily designed for 2D layouts, meaning it allows for the arrangement of elements in both rows and columns simultaneously. This capability is what distinguishes it from other layout techniques like Flexbox, which is more suited for one-dimensional layouts, either along a row or a column but not both at the same time.

With CSS Grid, developers can define complex grid structures, enabling them to place items precisely across a two-dimensional plane. This flexibility means that you can create both the horizontal (row-based) and vertical (column-based) arrangements within the same layout without needing additional styling or nested containers.

Mobile layouts can certainly benefit from CSS Grid, but it is not exclusive to them; Grid's functionality is broad and applicable to all types of interface designs, not just those optimized for smaller screens. Also, while hierarchical layouts can be implemented using Grid, they do not fully encapsulate the full potential of what Grid can achieve with its two-dimensional capabilities. Thus, recognizing CSS Grid’s primary design intention as being for 2D layouts is essential for effectively utilizing this layout system.