Playground
Two-axis lab
Category says what a measurement is. Status says how urgent it is. They may not share a surface. The fastest way to believe that is to try it.
Measurement category
What kind of thing this is.
Clinical status
How urgent this reading is.
Blood pressure
148/96 mmHg
Needs attention
Contact your care team about this reading. It is outside the range they set for you.
One chromatic surface, carrying one verdict, with the category supplied by a glyph and a label. Try removing the colour, then the word, then both.
Why a tool instead of a paragraph
The never-mix rule is easy to state and easy to agree with, and it is broken constantly. It is broken not by people who disagree with it, but by people building a “heart” card who reach for red because heart cards are red, and then need to show that this particular reading is fine.
The failure is invisible in the moment. It looks like a design choice, it passes contrast, and it only becomes a problem later, on a screen with several cards, when the reader has to work out which red is the one that means something.
So the lab refuses. Rather than putting a warning over a rendered example, it does not draw the combination at all, because the picture is what gets screenshotted and pasted into a ticket as evidence that it looked fine.
The greyscale test is the real one
Every status specimen in this system has to survive having its colour removed. Not because greyscale is common, but because it is a cheap proxy for four things that are: colour-vision deficiency, a printout taken to an appointment, a screenshot pasted into a document, and a phone held at an angle in bright sun.
A status that survives greyscale has three carriers and loses only one of them. The three are the word, the shape and the colour. A status carried by colour alone loses everything, and it fails silently: nothing errors, nothing looks broken, the reader simply does not know.
The generated colour-independence audit runs this check across every token pair rather than by eye. See colour independence for the measured version, including the colour-vision simulations this lab deliberately does not approximate a second time.
Where the rules are written down
The two colour axes is the doctrine page, and it is the one to read if you only read one. Clinical status semantics defines what each of the four levels means, who is allowed to assign it, and what it must never be read as. Category identity covers the other axis and what a category colour may not carry.
For the wording rather than the colour, writing status and alerts has the sentence pattern for each level and the words banned at each one. The two pages are meant to be read together: a status is a colour, a shape and a sentence, and the sentence is the part that travels furthest.
The ramps themselves are browsable at /colors, and the measured contrast for every pair is in the conformance table.