Drawing

It is always type="button", so it never submits a form. Any other button attribute, className included, reaches the button.

The parameter element worked this way and it is worth keeping — a value on a slider is something you read far more often than you set, so it is written as maths until the moment it is not. Enter and blur commit, Escape puts the old value back.

Same arrangement: the field and a hairline-divided trailing cell holding the two steppers, the browser's own spinners hidden so a stray scroll cannot alter a value. While it is being typed in it holds whatever was typed — including states no number can be, such as empty — and settles on blur, so clearing the field to retype it does not fight back with a clamped value.

Same arrangement, for the same reasons: the arrows sit OVER each edge rather than beside the row, on the page's own background, so a row that fits reads as a plain flex row and a row that does not keeps its full width. They fade in only when there is something that way, and the class that shows them is written straight to the DOM — a browser holds React's re-renders back during a scroll gesture to keep the scroll itself smooth, so a state-driven arrow would lag the finger.

Built rather than borrowed from the browser: a native range input styles differently in every engine, and this one has to sit in a row of maths without looking like it came from somewhere else. While a drag is running the handle follows the pointer exactly and the value it reports is stepped, which is the arrangement the parameter element used — a handle that jumps between steps under the finger feels broken even when the number is right.

A glyph element is drawn as given; otherwise name picks one of the built-in 24×24 paths, and with neither the span holds an empty SVG. The built-in SVG is hidden from screen readers, so an icon that carries meaning needs an aria-label.

Without a provider, reads come back undefined, which displays as an em dash, and publishing does nothing.

react-katex writes its output through dangerouslySetInnerHTML, so every render replaces a subtree of dozens of spans — the browser re-parses that HTML and lays it out again whether or not a character changed. An environment with a running animation renders every frame, which made every label on a plot and every reading in a footer a full typeset and relayout per frame.

Memoised on its source, so a formula that has not changed is not touched. Everything that sets maths goes through here. Notation that does not parse shows as the source text rather than an error.

The same row whoever is driving the letter. A cue.parameter sweeping through its years gets exactly what a hand-dragged parameter gets, because a reader looking at a moving number wants the same two things — to read it, and to be able to take hold of it. Dragging a swept one displaces it and it plays on from there; the transport that plays it sits in the TOOLBAR, where it drives the step's whole choreography rather than this one letter, and this panel folds away, which is no reason for the clock to stop.

The box is deliberately roomy and transparent; the flex alignment inside it is what puts the text exactly where align and baseline say. Nothing is clipped to it, so a label never loses a descender to its own container.

The SVG is labelled rather than hidden: a symbol stands in for a word (a tick for "yes", a house for "house"), so a reader who cannot see it loses the sentence, not a decoration.

Unmounting deliberately clears NOTHING. An environment leaves the tree when its scene scrolls away, but its session state — the reader's parameters, the fit they chose — persists, and the environment will resume it on return. The published values are the prose-visible face of that same state, so they persist with it; clearing on unmount would flash every citation back to an em dash whenever the reader scrolled past the environment's scene.

presenting is ctx.isPresenting; passing it is what schedules the settle-measure after the portal restage.

It starts clear of the mark's own ink and stops at the edge of the label's box, so it points at the words without touching either — a leader that runs under the letters reads as a strikethrough. Null when the two are close enough that the line would be shorter than the gaps at its ends, which is the case a leader is not for.

points is the four-point SVG polygon; base is its length from tip to back and arrowSize sets its width. trimX/trimY is where the line it caps should end, inside the notch, so the stroke does not poke through the tip.

A string is returned as is. It renders bold, italic, code, highlight, link (in a new tab), latex (with KaTeX, showing the source on a parse error), symbol, the colour names, and the six text functions; a bound expression renders as its live value. footnote, cite and internote go to the host's renderers in options when given, and to a plain fallback otherwise: a native tooltip, a raised dot, and a link to /{id}. An unknown micronode renders its body; a list or a block break renders nothing.

A spotlight is purely the dimming: everything else on the environment goes down around its content, which is left at full strength. No rings — a highlight is what rings something, and the two can be used together.