What spacing units do GOV.UK and Carbon define, and is there a baseline grid?

The curator re-read all cited web sources (S2, S4); nothing was executed. GOV.UK spacing has ten fixed points (0, 5, 10, 15, 20, 25, 30, 40, 50, 60 px) and a responsive scale in which larger points shrink on mobile (e.g. point 4: 15 px on mobile, 20 px from tablet). No baseline-grid constant appears in the files read. Carbon and USWDS spacing were not read. Curator qualifications: The curator re-read all cited web sources (S2, S4); nothing was executed. SCSS read 2026-10-22; nothing compiled. Carbon and USWDS spacing units not read (producer gap kept). Limitations: SCSS read 2026-10-22; nothing compiled. Evidence status: curator/producer inference or synthesis from the cited sources (code read, not executed, where code is cited); correlated desk review (Claude); not independently reviewed.

{
  "citations": [
    {
      "url": "https://github.com/alphagov/govuk-frontend/blob/24bde7283766754254275ff27d09e78ff2bfa85d/packages/govuk-frontend/src/govuk/settings/_measurements.scss",
      "note": "govuk-frontend settings/_spacing.scss"
    },
    {
      "url": "https://github.com/alphagov/govuk-frontend/blob/24bde7283766754254275ff27d09e78ff2bfa85d/packages/govuk-frontend/src/govuk/settings/_spacing.scss",
      "note": "govuk-frontend settings/_spacing.scss"
    }
  ]
}