Greenbar printout: pale bands carry the eye across dense rows, hairlines divide, and the ribbon has two colours. Ink records; red is the exception — a failed run, a breached ceiling, an unanswered question. Nothing is green, because a working system is not an achievement to celebrate on every row — except the header's pilot lamp, which reports that the daemon is alive rather than that anything succeeded.
Contrast, measured not guessed: ink 15.1:1 on paper, muted ink 4.7:1 on a band, red 6.2:1 on paper. In dark mode: 14.5, 5.1, 5.7. Failure marks separate from ordinary ones by ΔE 30 in normal vision and 17.5 under protanopia.