Fixed Documents

Documents: fixed dark mode readability

The Documents editor's page text, toolbar and comments panel are now readable in dark mode.

Typed text on the document page, along with footnotes, citations, the table of contents, page headers and footers, and the ruler, could render in low contrast against the page's paper background in dark mode. The toolbar above the page had a similar contrast problem. Both are fixed, and the comments panel now matches the app's dark surface instead of staying a literal white card.