[aenawi]

Target

• This is going into develop: the normal case for a fix, a chapter, a
  lab change, a typo
• This is a release: develop → main, shipping to the published guide
• This is a hotfix: straight into main, because published advice is
  currently locking readers out or leaving them exposed

What this changes

The board's nine colours move from the page's own tokens to nine --board-*
properties that default to them, which gives a stylesheet somewhere to stand
between the page and the drawing. A theme is then a folder under
control/ui/hud/themes/ holding theme.json and theme.css; themes.go
walks the embedded UI at startup and serves what it found at /api/themes, so
adding one is a folder and a rebuild with no list edited anywhere.

No issue — this was asked for directly. It is the first of a planned series;
what is deliberately not in it is listed at the bottom.

Kind

• Prose: clarity, typo, dead link
• The advice was wrong, unsafe, or out of date
• Lab or sandbox: code, checks, a new scenario
• A divergence between the lab and the sandbox, closed or newly documented
• Tests
• Something else

If this changes advice or a command

Not advice, but it changes behaviour, so it was measured rather than assumed.

OS: macOS 15 (Darwin 25.6.0), Docker Desktop
Browser: Chromium via CDP, headless
Go: as pinned in lab/control/Dockerfile
Measured on: 2026-09-12, against the lab running on this machine

What I ran, and what it printed:

$ docker compose up -d --build --no-deps control
 Container control Started

$ curl -s http://127.0.0.1:8099/api/themes
[
  {"id":"chapter","name":"Chapter","note":"The guide's own palette. …",
   "ground":"any","author":"the guide"},
  {"id":"warroom","name":"Warroom","note":"An operations wall: amber on …",
   "ground":"dark","author":"the guide"}
]

$ curl -s -o /dev/null -w '%{http_code}\n' .../hud/themes/chapter/theme.css
200
$ curl -s -o /dev/null -w '%{http_code}\n' .../hud/themes/warroom/theme.css
200

In the page, driving the picker:

  selecting warroom   --board-accent  #0d7a6f -> #e8a33d
                      --accent        #3ddbc7 (the page's dark token, untouched)
                      data-theme      -> dark          (the theme's declared ground)
                      data-hud-theme  -> warroom

  then the theme button
                      data-theme      -> light         (the button still wins)
                      --board-accent  #e8a33d          (the palette stays)

  selecting chapter   --board-accent  #0d7a6f
                      --accent        #0d7a6f
                      identical       true             (it overrides nothing)

  console errors      none

• I checked whether any other chapter makes the same claim — the nine
  colours were only ever read in one place, readTokens() in hud/scene.js
• If this step can lock someone out of a machine, the warning sits before the step — n/a
• The mechanism is explained, not just the command — lab/README.md gains a
  Themes for the board section with the nine properties and what each paints

Checks

• make -C lab check passes — "Everything held."
• gofmt is clean (make check fails on any output at all)
• New source files carry an SPDX-License-Identifier header

If this touches the guide's pages

It does not. Everything here is under lab/, which is the control server and
its embedded UI. The guide's own pages, assets/ and nav.js are untouched.

If this touches the lab or sandbox engine

The engine is untouched: no probe, no attack, no rung and no Result changed.
The only edit inside hud/ is the nine property names readTokens() reads.
Ticked because they were checked, not because they were assumed:

• Nothing is drawn that was not measured
• A failed attack does not render as a green tick
• danger still outranks ok
• Time is not faked
• The engine still returns the rung that decided the outcome, not a bare pass/fail
• If a score moved, the comparison table in lab/README.md moved with it — no
  score moved; the 27 board-rule tests pass unchanged

Licence

• I have the right to submit this, and I am fine with it going out under
  CC BY-SA 4.0 (guide) or GPL-3.0-or-later (code), per the file I touched

---

Not in this change

Kept out on purpose, one idea per branch:

• The feed. The readout cards want typed events — flows, rates, drop
  counters — rather than four separate SSE streams and a parser per consumer.
  That is its own branch and its own conversation.
• Widgets and slots. Cards docked around the board, declared by a theme's
  manifest rather than by index.html. Needs the feed first.
• The other skins. warroom is here as proof the seam holds, not as a
  finished look; it moves nine colours and nothing else, because nine colours
  is all a theme can reach today.
• Runtime-loaded themes. The store is //go:embed-ed, so a theme needs a
  rebuild. A mounted directory would remove that, and would also mean the
  control server — which holds the Docker socket — loading JavaScript from
  disk. Worth doing deliberately, later, if at all.