The chrome is now authored against Firefox design-token names with the shipped
value as a fallback `var(--fx-token, <literal>)` so colors, borders and radii
follow Firefox instead of having to be re-synced by hand.
In MOZCENTRAL viewer.css imports chrome://global/skin/design-system/tokens-brand.css,
gated on the new pdfjs.enableNova pref (default false, read straight from CSS via -moz-pref()).
With the pref off the sheet isn't applied, every fallback resolves, and the
viewer renders as before, as it also does in the GENERIC and components builds,
which never see the chrome sheet.
Consuming a token means never declaring its name in an unlayered rule, which
would shadow Firefox's for the whole subtree; --focus-outline, --border-color and
--text-color/--button-border-color are therefore renamed to
--editor-selection-outline, --signature-border-color and --views-*. In forced
colors each state reads a matching background/foreground/border triple so it
can't collapse to a single system color.
The dialog button styling also moves out of `.dialog .mainContainer button` into
a shared .primaryButton/.secondaryButton primitive (buttons.css, imported from
pdf_viewer.css so the components build gets it too). The password,
document-properties, print and undo-bar buttons use it in place of .dialogButton,
and the custom radio appearance gives way to native controls tinted with
accent-color.
Drop an external PDF anywhere in the views-manager thumbnail
sidebar to merge it at the cursor, rather than always inserting
after the current page via the "Add file" button.
The drop reuses the blue separator from page-move drag so the
user can see exactly where the inserted pages will land, and the
merge path is shared with the existing picker so post-merge
selection/current-page behavior stays consistent.
Update the styles and HTML to reflect the new views manager concept.
For now, nothing about split/merge functionality is implemented or visible.
The new styles for the outline, attachments, and layers will be added later.
The thumbnail view is now accessible with the keyboard.
