Colour architecture
===================

Spec: descriptive guidance, not a checkable rule.
It carries no forbidden and instead pair, and no `jig check` detector applies to it directly.
Section: Design Tokens

**Foregrounds are transparent. Backgrounds are solid.**

Foreground colours (text, icons, strokes, fills) are opacities of black in light mode and white in dark. Background colours are three solid elevation levels.

This is not a stylistic choice. A solid foreground looks correct on one background and wrong on the next — a grey tag reads as prominent on white and recedes into a grey panel. Dark mode has three background levels, so a solid fill is wrong on at least two of them. A transparent foreground mixes with whatever is beneath it and keeps a consistent prominence everywhere.

It also removes tokens rather than adding them: hover and press become transparent layers reused across every component and both modes.

**Three elevation levels**, consistent across modes: `base` (page), `raised` (cards, panels), `overlay` (dialogs, dropdowns).

- **Light mode:** shadows carry elevation, plus lighter-on-darker — a white card on an off-white page reads as raised without a shadow at all.
- **Dark mode:** shadows are nearly invisible. **Depth comes from the background colour**, so `--shadow-raised` resolves to `none` and the raised background does the work.

| | Light | Dark |
| --- | --- | --- |
| `text-strong` | black 90% | white 100% |
| `text-weak` | black 60% | white 78% |
| `stroke-strong` | black 45% | white 60% |
| `stroke-weak` | black 10% | white 12% |
| `fill` | black 4% | white 6% |

Brand and each system colour take the same four variations: **100%** text, **80%** stroke-strong, **20%** stroke-weak, **5%** fill.

**Neutral or monochromatic.** The default is neutral (pure black/white opacities), which works with any brand colour. For a monochromatic palette, tint the dark-mode backgrounds with the brand hue and, in light mode, replace the black opacities with a heavily saturated brand hue at low lightness. Change `--brand-h` and `--brand-s`; nothing else moves.