Unbounded line length

And do not let a layout choice push it far under. The readable band is 40–80 characters (02-tokens.md); the cap is the only half stated here, so a column can be halved indefinitely and still satisfy this rule while reading worse at every step. A narrow viewport that cannot reach 40 is a constraint and fine. Splitting a capped column into two side-by-side panels, and rendering prose at 41 characters in a mode whose own measure selects 68, is a choice — and it is choosing density over legibility, which is the trade M-01 says editorial does not make.