# Spec: Charts (Layer 09)

File: `src/layers/09-charts.css`

## Purpose

Data visualization using pure CSS and HTML tables. Inspired by Charts.css — uses `data-*` attributes to transform tables into visual charts.

## Scope

### In scope
- Bar charts (horizontal and vertical)
- Line charts
- Area charts
- Radial/gauge charts
- Chart axes, labels, legends
- Responsive chart sizing
- Chart color schemes using design tokens

### Out of scope
- JavaScript-powered charts
- Interactive chart features (tooltips on hover are CSS-only)

## Lineage

Inspired by Charts.css `data-*` attribute pattern. Not a port — reimplemented for ASW's token system and semantic approach.

## Constraints

- References only semantic aliases from `01-tokens.css`
- Charts must be readable without CSS (the underlying table has the data)
- Color choices must work for colorblind users