For designs/*/drawings/*.svg. Complements the format policy (AI-first SoT + builder print test).

Goals

  1. Print B&W on letter/A4 and still read high end, bottle, drains, tray.
  2. ≤ ~6 callouts on the hero side view.
  3. ASCII-only in <text> and comments (ImageMagick / some browsers choke on bad bytes).
  4. Agents can edit XML without a GUI.

Canvas & theme

Token Dark (site default) Print note
Background #1a2228 OK on screen; B&W print still works via stroke contrast
Drum / vessel fill #2a3540 Keep stroke light
Primary stroke #d0dce8 1.8–2 px vessel; 1.2 px frame
Dim / secondary text #9ab 11 px
Callout / note text #8bc 11 px
Feature (harvest / hinge) fill #3a6858, stroke #afd
Drain holes #5af (or #88aacc if print-weak) Small filled circles
Leachate tray / sump fill #243038, stroke #6a9 Distinct from vessel
PVC stroke #6a9, 3 px
Ground line #667788, 1.5 px

Title: 15–17 px bold, #e8e8e8. Body text: font-family: system-ui, sans-serif (or sans-serif only).

Optional print variant later: white background + #111 strokes—same geometry, swap <style> colors. Do not maintain two geometries.

Geometry conventions

Callout budget (hero side view)

Prefer these six (drop extras to detail drawings):

  1. Head (high / open)
  2. Stock lid (hinge at bottom)
  3. Harvest bottle under high end
  4. Drilled drains @ low point
  5. Leachate tray
  6. One dim: 36 deg or delta ~216 mm (not both if crowded)

Details (60 mm port, hole sizes, hinge hardware) live on harvest-port.svg / drain-pattern.svg.

File hygiene

Flows (not dimensioned)

Author as Graphviz .dot (preferred) or Mermaid .mmd under designs/<scale>/diagrams/ or assets/diagrams/. Pre-render:

dot -Tsvg diagrams/foo.dot -o drawings/foo.svg

Flow SVG may use a lighter style (boxes + edges); still dark background + ASCII labels; no CDN renderer on the live site.