Overture website update

.gitignore

@@ -3,6 +3,7 @@
 
 # Production
 /website/build
+/website/build-marketing
 
 # Generated files
 /website/.docusaurus

AGENTS.md

@@ -16,6 +16,16 @@ The canonical task→convention dispatch table lives in `~/.claude/agentics/temp
 ## Project context
 Overture Docs is the **centralized documentation site for the Overture stack**, built with [Docusaurus](https://docusaurus.io/). It aggregates Markdown from the `/docs` directory of each Overture project repository (pulled in as git submodules) and renders them as one navigable site. The point of the setup is that documentation stays with its source project while readers get a single hub. Full overview in [README.md](README.md); planned work lives in `.dev/roadmap.md`.
 
+## Verifying a UI change
+
+A clean `npm run build` says a page compiled, not that it looks right. Before calling any visual change done, render it and look at it.
+
+- Build and serve: `cd website && npm run build && npm run serve --port <port>`. `npm start` renders in the browser, so its HTML is an empty shell and tells you nothing.
+- Screenshot with a real browser at a real viewport. Chrome's `--headless --screenshot --window-size` is unreliable: the window size is not the CSS viewport, and it will show you clipping and overflow that do not exist. Drive it with `puppeteer-core` and `page.setViewport` instead, pointing `executablePath` at the installed Chrome. Install it outside this repo (the scratchpad), never as a dependency here.
+- Check the widths that change behaviour, not just the one you are working at. The marketing navbar collapses at 1160px.
+- When something looks wrong, measure it in the page (`getComputedStyle`, `getBoundingClientRect`, `scrollWidth` against `clientWidth`) before changing CSS. Reading a screenshot is guessing.
+- Check a documentation page too whenever marketing styles or theme components change: the two sites are separate builds but one codebase, and `src/theme/` and the emitted stylesheet are shared by both. `npm run build` and `npm run build:marketing` both have to pass.
+
 ## Project-specific constraints
 - **Public repository** (`overture-stack/docs`): no credentials, secrets, tokens, or private URLs in any committed file, ever.
 - **Documentation content is owned by the submodules, not this repo.** Each project's docs live in `submodules/<project>/docs/` and are symlinked into `website/docs/`. Edit the **source** file under `submodules/<project>/`, never the symlinked copy under `website/docs/`: editing through the link mutates the vendored submodule's working tree in a way that is easy to lose and confusing to review. Symlinks are (re)generated by `symlinker.sh`.
@@ -24,7 +34,11 @@ Overture Docs is the **centralized documentation site for the Overture stack**,
 
 ## Repository orientation
 - `submodules/` — vendored Overture repos as git submodules: `arranger`, `lectern`, `lyric`, `maestro`, `score`, `song`, `stage`, and `.github`. Each carries its own `/docs`. Defined in `.gitmodules` (see `.dev/roadmap.md`: release-branch tracking is not yet configured, so `git submodule update --remote` currently follows each repo's default branch).
-- `website/` — the Docusaurus site: `docs/` (aggregated, symlinked from submodules), `community/`, `guides/`, and `src/` (`components/`, `css/`, `theme/`, `pages/`).
+- `website/` — the Docusaurus site: `docs/` (aggregated, symlinked from submodules), `community/`, `guides/`, and `src/` (`components/`, `css/`, `marketing/`, `theme/`, `pages/`).
+- `website/src/marketing/`: everything the overture.bio site is made of: its routes under `pages/` (whose `index.tsx` is the home page at `/`), plus components, constants, case-study data, and the Sass tree. Its styles are all imported inside `.marketing` by `styles/index.scss`, and only `MarketingPage.tsx` imports that file, which is what kept those bare class names and element rules off the documentation pages while one build served both. The builds are separate now, so this is belt and braces, but the scoping stays: `src/theme/` is still shared. Add marketing styles as a partial imported there, never as a stray `import "./styles.scss"` in a component.
 - `symlinker.sh` — regenerates the symlinks that bring selected submodule `/docs` files into `website/docs/`.
+- **Two sites, two builds, one branch.** `docusaurus.config.ts` reads `OVERTURE_SITE`: unset it builds docs.overture.bio (`npm run build`), `marketing` builds overture.bio (`npm run build:marketing`). The marketing build drops the documentation plugin instances and the redirect table, and points the pages plugin at `src/marketing/pages/`. Both builds keep Algolia: `MarketingNavbar` renders the same `@theme/SearchBar`, and the marketing build adds `externalUrlRegex` so results navigate cross-host to docs.overture.bio instead of 404ing. Components ask which build they are in through `useIsMarketingSite`, never by inspecting the route.
+- `website/static-docs/` and `website/static-marketing/` — what each host owns alone: `robots.txt` for both, and the `_redirects` file each one publishes. `website/static/` is still shared. There is deliberately no `netlify.toml`: one file on one branch cannot say different things to two Netlify sites, and `docs.overture.bio` is configured through the Netlify UI. Redirects belong in the `_redirects` file of the host that owes them.
+- `website-legacy/` is **gone** as of 2026-08-07. It was a staged copy of the [overture-stack/website](https://github.com/overture-stack/website) Gatsby site, kept while the port ran. Everything it held is either ported into `website/` or still in that repo, which serves overture.bio until DNS is cut over to the marketing build here, and is cloned locally at `~/Desktop/website`. Until that cutover, a change that has to reach the live overture.bio goes there, not here.
 - `README.md`, `preview.png` — human-facing project overview and screenshot.
 - Local setup: Node 18+, `npm ci`, then `npm start` (see `README.md` § Getting Started).