Consistency in viewport size versus consistency in relation to the width of text. It's a little bit of a "top-down" versus "bottom-up" distinction in thinking.

Consistency in viewport size versus consistency in relation to the width of text. It's a little bit of a "top-down" versus "bottom-up" distinction in thinking. (I often find the best answer is "both". vw/vh for "big picture" alignments like outermost grid structures and ch/em/lh/ex for "content" work inside those big grids.)