The final pass

#What the compiler checks

The compiler refuses these. Fixing them makes the document valid, not right.

• A callout in a scene's detail: node `definition` is not allowed here (allowed: …).
• A third environment beside two: A scene detail holds at most two canvas environments; found 3 — a grid holds up to nine.
• An anchor past the last step marker: 'cue.in' anchors to step 3, but the scene has 1 step (valid: 0–1).
• A question without an id: A question needs an id to remember the reader's answer by — write question#name:….
• A colour, highlight or symbol in the narrative: '!teal' is not allowed in the narrative; colour, highlighting and symbols belong in the canvas.
• A citation of a source the document does not declare: unknown id `#nobody`.

It warns on these, and compiles anyway.

• A direction or ratio on a detail with one environment: 'direction'/'ratio' only apply when the detail declares two canvas environments.
• A dollar sign meant as money: '…' is set as maths: two '$' signs on one line open a maths span. Write a dollar sign as \$.

#What nothing checks

Nothing checks these. Each links to the page that gives its reason.

• The document teaches the topic its title names, with the constructs and the length that topic needed. What a document covers
• Each canvas makes one point, a second idea is a new scene, an empty detail is left empty, and a heading marks a section of the argument rather than a scene. Scenes and what each shows
• The prose describes the canvas's state, names marks by what they are, and never locates the canvas or another scene. Prose & canvas state
• The prose explains rather than narrates, the headings name their content, no pronoun points at a sentence that became a heading, and maths is LaTeX wherever LaTeX is legal. Prose & headings
• Prose introduces every callout, each definition's term stands alone in a glossary, and each note is an aside. Callouts
• Every computed number is read with a {{…}} expression and rounded for the claim. Reading computed values in prose
• Every mark changes what the reader understands, each detail reads on its own full screen, and a split's direction is left at auto. Selecting canvas content
• Domains are written only where the window is part of the claim, size and width are left at their defaults, each mark is declared once, ticks match what the prose reads, and each hue means one thing. Framing a readable graph
• New content arrives on the step that introduces it, every marker has something anchored to it, timers carry only timed motion, sweeps show a change the prose describes, and every parameter's prose holds at both ends of its range. Steps, timers, sweeps & parameters
• Each question shares its canvas only with what it needs, sits opposite the task that sets it, follows the reasoning rather than the answer, and each task carries its worked answer. Questions & tasks
• The map's tree follows the dependencies between its ideas, counts prompted a check rather than set a target, the root opens in a way chosen for its subject, and no opening scene links forward to a topic the tree places later. Shaping a map from its subject
• Each worked result is derived in one internote and each term defined in one, and the others quote and link there. One home for each result and term
• Every other number was worked out, every quoted output came from a run, every dataset was read before it was described and attached whole, and every external fact was checked and cited, or cut. Checking a document's claims
• Groups match their nodes, booleans are bare and last, keys are spaced, durations are in seconds from one second up, rows are in @data and repeated expressions in @let. Source style