M4.96: Window › CSS Properties shows, copies and exports the CSS of the selection

The svg crate's new CSS writer (css_rules) gives the CSS web pages style objects
with: rectangles and ellipses as background-color / linear-/radial-gradient(),
border and border-radius; type as font, color, spacing and alignment; shadows,
glows and blur as box-shadow, text-shadow and filter. It shares SVG export's
declarations (transparency, fonts, type spacing, colours, gradient stops), which
moved into svg/src/css.rs. Options: units, absolute position, width and height,
unnamed objects, rasterize unsupported art (as a PNG background-image).

Commands css.selection, css.generate and css.export; UI commands css.copy and
css.exportFile; the CSS Properties panel with a highlighted code view.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/control-protocol.md

@@ -34,6 +34,7 @@
 | `engine.execute` `file.exportForScreens` | `{}` / `{…document.exportForScreens params}` | without params opens `exportForScreens` on the settings the document last exported with (`document.exportSettings`). Fields: `tab` (`artboards` \| `assets`), `select` (`all` \| `range` \| `full`), `range` ("1-3, 5"), `boards` (a bool per artboard; checking them sets `select` and `range`), `includeBleed`, `folder` (desktop; default the Desktop, else home), `openLocation`, `subfolders`, `prefix`, `preset` (`""` \| `mobile` \| `density`), `formats` (rows `{format, scale: "2x" \| "100w" \| "100h" \| "72ppi", suffix, quality?, folder?}`), `settings` (`{png \| png8 \| jpg \| webp \| gif \| svg \| pdf: {…options}}`, the gear's Format Settings; `__settings` names the format shown). `ui.dialog.confirm` exports (a bad range or no folder keeps it open); on the web OK reads "Download" and the files download (several as one `.zip`). With params it runs `document.exportForScreens`: no `folder` returns the files (or with `zip: true` one store-only zip) as `dataBase64`; with `openLocation` the first file is shown in the file manager |
 | Export for Screens' Assets tab, Asset Export panel | `ui.dialog.set` `tab: "assets"`, `assets: [asset id…]`; `window.panel {panel: "assetExport"}` | on the Assets tab of `exportForScreens` the `assets` field lists the checked asset ids (all of them when it opens); `ui.dialog.confirm` runs `document.exportForScreens {assets}` (nothing checked keeps it open) and OK reads "Export Asset". The Asset Export panel acts through `assets.*` and shares the format rows with the dialog (`assets.settings.set`) |
 | `engine.execute` `file.exportSelection` | `{multiple?}` | File › Export Selection…: collects the selected objects as assets (`assets.add`; one per object unless `multiple` is false) and opens `exportForScreens` on its Assets tab with just them checked → `{assets}`. `document.exportSelection` still exports the selection in one go, without the dialog |
+| CSS Properties panel | `window.panel {panel: "cssProperties"}`; `engine.execute` `css.copy` / `css.exportFile` | the panel shows `css.selection` of the selection (after Generate CSS, while nothing is selected, `css.generate`); its menu holds the options the commands take (`units`, `position`, `dimensions`, `unnamed`, `rasterize`). `css.copy {scope?, …options}` copies the CSS to the clipboard → `{css, rules}`; `css.exportFile {path?, scope?, …options}` writes `css.export` to `path` (else a picked file; the web downloads it) with the pictures of rasterized art next to it → `{path, rules, images}` |
 
 | `ui.dialog.*` on `importPdf` | `{field: "page" \| "allPages" \| "range" \| "cropTo" \| "password", value}` | opening (`app.open`, `file.open`) a PDF or `.ai` with several pages or a password, or placing one (`file.place` without `page`), opens the Import PDF dialog (`mode`: `open` or `place`; `pageCount`). While `__locked` is true, set `password` and `ui.dialog.confirm` to unlock it (a one-page file then opens or is placed). Then set `allPages: false` and `range` ("2-3, 5") to open some pages, or `page` to place one, and `cropTo` (`bounding`, `art`, `crop`, `trim`, `bleed`, `media`); `ui.dialog.confirm` opens or places them (placing keeps the other `file.place` params, such as `link`, `template` and `at`, in `__place`). `document.open {pages, cropTo, password}` and `file.place {page, crop, password}` do the same without the dialog |