Built-in Themes, the picker and the page's own look

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The built-in Themes, and the page setting its own look (ADR 0016 as amended, ADR 0018).

Six Themes: Focus (the default), Plain, Press, Signal, Garden and Factory, each in auto, light and dark. They're compiled in, with their fonts embedded as Latin-subset woff2 files at the weights they use. All ten families are under the SIL Open Font License.
The tokens: a Theme is only tokens: colours, fonts, type, shape, tags, effects and motion. Text on a solid fill is black or white, whichever reads better.
The picker opens with Shift+T. It writes the chosen Theme to the User config's [console] section.
The Sections chooser hides sections, also saved under [console].
CLI equivalents: thirdshift console theme <name>, console theme list and console sections [--hide …] [--show …] do the same from the CLI.
Config writes keep the file's comments and layout, as Setup's do. They never touch anything outside [console]'s look keys, and each one goes in the Console log naming the account.
Motion is only for thirdshift's activity:
- the Working spinner;
- the heartbeat dot;
- the latest-line flash;
- the live log cursor;
- the stopping bar;
- the running stage's stripes;
- the Silent alarm, which pulses three times, then holds.
Factory's conveyor and Garden's bed move only while a Command is live. Pause motion stops it all, per browser, and prefers-reduced-motion is respected.

All six Themes render in auto, light and dark, with no font loaded from another site.
A test checks AA contrast for every text-on-background pair in every built-in Theme.
Choosing a Theme or hiding a section on the page, or with the CLI, changes only those keys in [console], keeps the comments, and writes a Console log line.
The page can't write any other key.
Both routes are paired with their CLI commands in the parity test.
Nothing moves when no Command is live. Pause motion and reduced motion stop everything.
Playwright covers switching Themes and Pause motion.