Copy and rebase user-declared stylesheets (format.html.css) — bd-format-css-not-copied-crn3bjdz

claude-notes/plans/format-css-not-copied-investigation/README.md

@@ -0,0 +1,29 @@
+# Investigation artifacts for bd-format-css-not-copied-crn3bjdz
+
+`repro/` is a minimal website project mirroring the external repro at
+`~/repos/github/cscheid/q2-connect-docs/llms-info/repros/format-css-not-copied/`
+(source of truth for the Q1 comparison table).
+
+Run:
+
+```bash
+cargo run --bin q2 -- render claude-notes/plans/format-css-not-copied-investigation/repro
+```
+
+Expected (buggy) behavior at `main` @ `10d86829`, confirmed 2026-08-14:
+
+- `_site/styles.css` and the extension css are **not written** anywhere in
+  the output tree;
+- both `<link>` hrefs are emitted **verbatim at every depth**
+  (`styles.css` on `deep/deeper/index.html`, beside a correctly rebased
+  `../../site_libs/quarto/quarto-theme-*.css`);
+- render is clean: exit 0, no diagnostic.
+
+Note `_extensions/acme/widget/` deliberately contains only `widget.css` —
+no `_extension.yml` — so no extension machinery is involved; the path just
+happens to point into `_extensions/`.
+
+The rendered `_site/` is not committed; re-render to regenerate.
+
+See `claude-notes/plans/2026-08-14-format-css-not-copied.md` for the full
+investigation and design questions.

claude-notes/plans/format-css-not-copied-investigation/repro/_extensions/acme/widget/widget.css

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+body { --repro-extension-css: 1; }

claude-notes/plans/format-css-not-copied-investigation/repro/_quarto.yml

@@ -0,0 +1,9 @@
+project:
+  type: website
+website:
+  title: "format css"
+format:
+  html:
+    css:
+      - styles.css
+      - _extensions/acme/widget/widget.css

claude-notes/plans/format-css-not-copied-investigation/repro/deep/deeper/index.qmd

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+---
+title: Deep page
+---
+
+Two directories below the site root.

claude-notes/plans/format-css-not-copied-investigation/repro/index.qmd

@@ -0,0 +1,5 @@
+---
+title: Root page
+---
+
+At the site root.

claude-notes/plans/format-css-not-copied-investigation/repro/styles.css

@@ -0,0 +1 @@
+body { --repro-project-css: 1; }

crates/quarto-core/src/pipeline.rs

@@ -1284,6 +1284,12 @@ pub fn build_transform_pipeline(
     pipeline.push(Box::new(WebsiteFaviconTransform::new()));
     pipeline.push(Box::new(WebsiteBootstrapIconsTransform::new()));
     pipeline.push(Box::new(WebsiteCanonicalUrlTransform::new()));
+    // User-declared stylesheets (bd-format-css-not-copied-crn3bjdz):
+    // copy `css:` files into the output tree and rewrite the entries
+    // to per-page hrefs. Not website-scoped — default projects (and
+    // books, which ride the same dispatch) and single-doc renders get
+    // the same treatment. Self-gates to HTML-family formats.
+    pipeline.push(Box::new(crate::transforms::FormatCssTransform::new()));
     // Draft marking (bd-draft-banner-missing-hgx1gkqm). Not website-scoped
     // — a standalone `draft: true` document gets the banner too — but it
     // belongs with the metadata producers above: it only writes