Skin

None, then four steps each twice the one below, then a pill. Two steps apart is the same distance wherever you stand on the scale, which is what makes it readable. The first step is barely there on purpose: it is what a flat skin wants when a true right angle reads as unfinished. Anything rounder than the last step is a shape that wants to be a circle and says so itself — a circle is not a skin decision.

A shape never reads the scale above: it reads the role it plays, and the skin says which step that role gets — never what a step is worth, which would make the scale mean two things at once. What holds something is a box, whether it holds text, content or a message; what separates two regions of a page is neither, and rounds nothing. Switch the skin to `soft` and watch a control part ways with the rest: a capsule is right for something one line high and absurd for a textarea.

Four depths, from a hairline lift to a floating panel. A skin that wants a flat world sets all four to none and every raised surface follows.

The line itself — its width and its style. Its colour is not here: that belongs to the colour scheme, which is what lets a skin remove a line without knowing what colour it would have had.

The two lines that tell things apart: between two rows of one thing, and between two regions of a page. Twenty-odd shapes read the first one, which is why it is a token and not a rule.