The docs site rendered as stock Material: indigo header, indigo links and
Open Sans. Neither colour nor type matched the marketing site
(datacontroller.io) or the application itself.
- Palette: the slate (#314351) and green (#79a843) already used by the
marketing navbar, hero and logo accent, wired up via a `custom` palette
and defined in the new docs/dc-brand.css.
- Type: Montserrat for text, matching the marketing site's headings.
- Logo: the application's own dc-logo.svg mark in the header.
The previous `palette:` mapping form (a dict of primary/accent) is no
longer honoured by the Material version this repo builds against, so the
theme fell through to Material's default indigo - the site was not in fact
rendering the White/Amber it asked for. The list form used here is the one
Material currently reads.