diff --git a/docs/content-model.md b/docs/content-model.md
index fdd65f6..eab9c67 100644
--- a/docs/content-model.md
+++ b/docs/content-model.md
@@ -30,6 +30,8 @@ Files are content-addressed (blake3[:12] + extension) and stored **on disk** und
`Data.theme` is the active theme name (empty = none/base only); themes are folders in `pagerite/themes/{name}` containing `theme.css` and/or `banner.css` (+ `banner.svg` artwork and any extra assets the CSS references, like summer's `grass.svg`), served by the backend at `/_themes/{name}/...` — read from disk per request (etag by mtime), never built, so on-disk edits show on the next page load even in prod. The theme selector and banner-design selector enumerate these folders via `GET /_api/settings`.
+`Data.transition` is the page-transition design name (default `cube`): a theme folder shipping `transition.css`, injected as `#pagerite-transition` on every page and selected in the site editor (the selector enumerates `transition.css` folders via `GET /_api/settings`). See `docs/themes-and-assets.md`.
+
`Data.custom_css` is raw trusted CSS injected inline in every page `
` (id `pagerite-user`) and swapped during fetch-navigation; editable in the site editor. Font picks (heading/body/brand) in the site editor are stored as plain `:root` rows in `custom_css` (`--font-body: var(--font-source-sans);` format — parsed out and rewritten on change, the `:root` block added/removed as needed), referencing the per-family variables (`--font-source-sans` etc.) from `pagerite.css`; the base stylesheet's `--font-brand` defaults to `var(--font-heading)`.
`Data.favicon` names a file in the content-addressed store (on disk under `/files/`), uploaded/cleared in the site editor via `PUT`/`DELETE /_api/settings/favicon`; when set it is linked as `` on every page, otherwise browsers fall back to the build's `/favicon.ico` by convention.
diff --git a/docs/design-principles.md b/docs/design-principles.md
index 2a6fc80..901fcb5 100644
--- a/docs/design-principles.md
+++ b/docs/design-principles.md
@@ -26,7 +26,7 @@ Pagerite is a single-user CMS/blog. This document records the initial high-level
- All pages share one static layout, defined once as an **html5tagger Template** with capitalized placeholders (`Title`, `Banner`, `Nav`, `Sidebar`, `Main`) filled per request. The dynamic regions carry stable ids (`#page-banner`, `#nav`, `#sidebar`, `#main`).
- The page top is a **full-width banner header** with the site name and the navigation bar overlaid on it — no separate chrome header. The banner combines two layers, stacked in `#page-banner` (a grid, so they overlay): first the **banner design** — a named design living in a theme folder (`pagerite/themes/{name}/banner.css` plus artwork as `banner.html` — arbitrary markup like canvas + style + script — or `banner.svg`), chosen per page via `Node.banner_design` (a design name, "" for none, None to inherit from the nearest ancestor, then the front page, then the active theme's own design). The artwork is inlined into a `div[data-design]` wrapper: SVG artwork can be recolored from the theme stylesheet (corporate's single SVG serves both light and dark mode via `var()`-driven stops). Second, **per-page author code**: `Node.banner` holds an arbitrary trusted HTML snippet (an image, a styled div, canvas + script — anything), resolved by walking up the node's ancestors to the front page and rendered **after** the design artwork, so author styles always win over the design's own. The base stylesheet falls back to a plain gradient. There is deliberately no scrim fading the banner into the page background — any such fade would ruin user-supplied designs; themes that want one bake it into their SVG (purple does).
-- **Fetch-navigation.** Links are plain ``; a small script (`frontend/src/pagerite.js`) intercepts same-origin clicks, fetches the page, and swaps the `#page-banner`, `#nav`, `#sidebar` and `#main` regions, the document title, and the site-wide custom CSS (`