add(foundations): CSS subgrid page#82
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New spec page documenting the `grid-template-columns: subgrid` / `grid-template-rows: subgrid` value (CSS Grid Layout Module Level 2), which lets a nested grid inherit its parent's tracks so cards, form rows, and list items align across the whole layout without magic numbers or JavaScript measurement. Status: recommended — a layout improvement, not a platform requirement. Baseline widely available across Chrome, Edge, Firefox, and Safari since September 2023 (verified via MDN BCD). Wires relatedSlugs on container-queries and anchor-positioning, adds a changelog entry, and regenerates the count-driven OG images. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Closing after review: this is out of scope for the spec as it stands. The spec describes auditable outcomes of a good website (platform contracts, behaviours you can verify from outside), not build techniques. "Uses subgrid" is not a property of a good website — a site laid out entirely with flexbox is no worse, and there is nothing to audit. Recommending a Level 2 refinement of CSS grid while the spec says nothing about grid or flexbox at all would also make the checklist incoherent: readers whose sites do not use grid would get a tickbox they can never meaningfully tick. Two further problems, for the record: The difference from pages like container-queries or popover-api is that those map to user-facing outcomes (components adapt to available space; native semantics and dismissal). Subgrid's benefit is developer convenience. The daily-standards-scan routine has been updated to filter proposals against "auditable website outcome, not build technique" so this class of proposal is not raised again. The writing quality here was good — this is purely a scoping call. |
… techniques The daily standards scan proposed a CSS subgrid page (PR #82, closed): well-written, but subgrid is a build technique whose benefit is developer convenience, not an auditable property of a good website. Add an explicit scope rule with the outcome test so the scan skips this class of proposal. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Judged all pages by the scope rule added after PR #82 (auditable website outcome, not build technique): - Downgrade View Transitions, invoker commands, and visibility-aware rendering from recommended to optional — real platform features, but context-dependent polish, below the 'a modern site should do it' bar. - Remove entry-exit-animations and field-sizing — CSS features whose benefit is authoring convenience; nothing for a visitor, crawler, or agent to gain and nothing to audit. - Clean relatedSlugs on popover-api, reduced-motion, invoker-commands; unlink the now-dead links in the 1 July changelog entries. - Changelog: one status entry, one removed entry. - Regenerate OG images (count-driven + status badges on the three downgraded pages); delete the two per-page images. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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What
Adds a new spec page: CSS subgrid under
foundations.Documents the
grid-template-columns: subgrid/grid-template-rows: subgridvalue — a nested grid inheriting its parent's track sizes, so cards, form rows, and repeating list items line up across the whole layout without magicmin-heightnumbers or JavaScript measurement. Canonical sections (What it is / Why it matters / How to implement / Common mistakes / Verification), British English, ~450 words.Why now
A genuine gap: the spec covers modern CSS layout primitives (
container-queries,anchor-positioning,field-sizing) but not subgrid, one of the most impactful of them. Cross-component alignment is a real, common outcome the spec should describe.Primary source & status
grid-template-columnsreference.css.properties.grid-template-columns.subgrid).Status:
recommended— it materially improves layout robustness, but the platform contract does not break without it, so it is notrequired.Also in this PR
relatedSlugswired oncontainer-queriesandanchor-positioning.added, 2026-07-06).og-default,checklist,spec,spec/foundations) + the new per-page image.npm run buildpasses; page appears on/spec/,/checklist/,/llms.txt, and is served at.md. Left as a draft for maintainer review — do not merge automatically.🤖 Generated with Claude Code