Units and functions

Resize the window and watch which boxes move and which hold still.

width: calc(12rem + 2vw) — a fixed part plus a viewport part.

width: min(90%, 30rem) — fluid, capped at 30rem.

width: max(50%, 16rem) — never below half the page or 16rem.

This paragraph is capped at 60ch — the width of sixty "0" glyphs — which is how line length is expressed in the unit that actually measures text.