vw/vh/vmin/vmax)The "viewport" for a paged medium is the page box itself. Every shape below is sized purely from a viewport-relative (or cq*/ch) unit, so a broken conversion would collapse it to nothing rather than just the wrong size.
width: 100vw
width: 60vw
width: 25vmax
height: 25vmin (square - the page's shorter side)
width: 50cqw, no ancestor container-type - falls back to 50svw (the page's own width), not 0
width: 20ch - approximates 10em (0.5em per "0" glyph)