@polyxd/ds-govuk

@polyxd/ds-govuk

GOV.UK Frontend as a Polyxd design-system pack: DTCG 2025.10 token files that satisfy the semantic token contract.

npm run check -w @polyxd/ds-govuk     # contract check
npm run generate -w @polyxd/ds-govuk  # regenerate tokens/*.json

Source

govuk-frontend 6.5.1 (MIT). GOV.UK publishes compiled component CSS and no token file at all: its palette, functional colours, spacing points, measurements and type scale live in Sass settings, as maps. Those six settings files are vendored verbatim under scripts/sources/govuk, and the generator reads their maps directly — narrowly, by the shape of each map, rather than by evaluating Sass.

Names are kept: govuk.palette-blue-shade-25 for a palette colour, govuk.link or govuk.secondary-text for a functional one, govuk.spacing-4, govuk.font-size-19.

One mode

GOV.UK has one theme. There is no dark mode to read, and this pack does not invent one: it ships a single mode, and the theme compiler renders it whichever mode a surface asks for. A dark-mode surface in a GOV.UK pack is a light GOV.UK page, which is what GOV.UK is.

What GOV.UK doesn't have, and what the pack does

Contract token	GOV.UK	What the pack uses
radius.*	square corners, everywhere	0 — the one shape decision the whole system is built on
shadow.raised, shadow.overlay	no shadows at all	a zero, transparent shadow: depth is a border, not a blur
motion.duration.*	nothing animates	zero, rather than an invented curve
color.border.focus	a yellow block with a 4px black bar under it	the black bar — the yellow alone is 1.35:1 on the page, and a single-colour ring can't be both halves
color.status.warning.*	its warning component is black text beside a black icon	its orange, which the palette carries for exactly this weight of message
type.label.small	the scale stops at 16px	16px — GOV.UK has no small print, which is the point of the system

Where a role does have to move, it moves along GOV.UK's own variants of the same colour (primary, tint-25…tint-95, shade-25, shade-50), sorted by measured luminance. In 6.5.1 the only moves are in orange: orange-primary is 2.25:1 on white, so accents take orange-shade-25, and panel text takes orange-shade-50.

Files

File	What's in it
tokens/system.light.json	GOV.UK's palette, functional colours, spacing and type scale, plus the polyxd.sys.* additions
tokens/semantic.json	the Polyxd contract, each token an alias
manifest.json	the one mode, contract version, provenance
scripts/sources/govuk/	the vendored Sass settings and GOV.UK's licence