[Arthurvdv]

Closes #137.

The site shell (header, dark mode, mobile menu, footer, design tokens) stays own CSS. The owner chose it after the spike built the landing page and stages/default/ twice; the result comment with the criteria table and the 16 screenshots is #137 (comment).

Spike result

• Hextra passed every hard constraint after trimming. No resources.GetRemote is left (I removed the remote-icon branch of utils/icon.html). The build runs offline, the output has no CDN reference, it needs 12 files, and the 628-row matrix needs no fight with the theme CSS.
• Little of Hextra's shell survives. Its navbar builds its links from the site configuration, not from rulebook.json. Its menu script throws without a sidebar. Its footer is built around the theme credit. Its head and scripts fingerprint the asset paths. What we kept was the compiled CSS and a theme toggle.
• The compiled CSS has a class gap. It contains only the classes Hextra uses: 14 of the first classes our layouts wrote did not exist and failed silently (our layouts use 132 distinct hx: classes). Hextra's dark mode needs JavaScript, so without it the site stays light even on a dark system.
• Volume and maintenance. Hextra adds 12 files and 163,141 B under site/themes/hextra/ (main.css is 144,984 B) to every organization repository and to the D35 compare. Each Hextra release means repeating three trims: icon.html, icons.yaml, and leaving out theme.toml. Copied as is, theme.toml (blob/main/) and icons.yaml ("v1") break the Deploy forbidden-literal test. Own CSS adds no file under themes/; its site.css is 15,881 B.
• Look. Own CSS gives the dense developer-tool look and follows the system dark setting without JavaScript. The tokens meet WCAG AA: in light mode, text 15.8, muted 6.1, accent 5.2, chips 5.3 to 6.4; in dark mode, text 16.0, muted 6.5, chips 6.2 to 7.5.

Scratch branches (never merged)

• wp16/spike-own-css: the shell PR WP16: design system and app shell (tokens, logo, header, dark mode, mobile, sticky matrix, favicon, Open Graph, footer) #138 starts from it; delete it once WP16: design system and app shell (tokens, logo, header, dark mode, mobile, sticky matrix, favicon, Open Graph, footer) #138 has taken what it needs.
• wp16/spike-hextra: delete it after this PR merges.

The plan put both variants on one branch; I used two so each can be checked out and built as it is.

Files

• docs/adr/0059-the-site-shell-is-own-css-and-no-vendored-theme.md: the new ADR D59. It confirms D31 and D35, which stand unchanged, and rejects a theme vendored into site/ as a further alternative; Hugo Book was not built, because no constraint failed. It also notes the D58/D59 renumbering.
• docs/adr/README.md: index row and reference line.
• docs/dashboard.md section 3: one paragraph naming the decision.
• docs/reference/spikes/wp16-shell/README.md: the spike record (question, method, criteria table, screenshots, answer, notes for WP16: design system and app shell (tokens, logo, header, dark mode, mobile, sticky matrix, favicon, Open Graph, footer) #138), plus the 16 PNGs (40 to 133 KB each).
• (no change to docs/reference/spikes/README.md, which indexes the WP01 spikes)
• RELEASENOTES.md: one line under ## v1.0.0-beta.8.

Nothing under template/ changes.

Tests

• Invoke-Pester -Path ./tests/Docs.Tests.ps1 -Output Normal, with RULEBOOK_DOCS_PATH set to the template docs: 340 passed, 0 failed, 0 skipped (again after review round 1).
• On both scratch branches, the forbidden-literal regex of the Deploy test over template/site finds no hit, and the CDN grep of both builds is empty.

🤖 Generated with Claude Code