/**
 * The runtime graph's VISUAL VOCABULARY, and the legend that explains it.
 *
 * Every colour, shape and fill the drawing uses lives here, next to the legend swatches that teach
 * the reader what each one means. They are one unit on purpose: the legend's job is to be a true
 * account of the picture, and the fastest way for a legend to start lying is for it to sit in a
 * different file from the constants it describes and drift as those change.
 *
 * Imported by runtime-visualizer.ts, which owns the DRAWING (which nodes and edges to emit). This
 * module knows nothing about the graph model, which is what keeps the dependency one-way and
 * cycle-free.
 */
export declare const LEVEL_COLORS: Record<number, string>;
export declare const QUEUE_FILL = "#FFF3E0";
/**
 * The queue node is an `Mrecord` whose FIRST field is empty, which draws a rounded outline with a
 * vertical cap line near one end — a cylinder lying on its side, distinguishing a queue from the
 * upright cylinder that now means a database.
 *
 * Two things here are load-bearing and easy to break:
 *
 * 1. NO surrounding `{}`. Record fields lay out along the rank direction, and this graph is
 *    `rankdir=TB` (see {@link generateRuntimeDot}), where the default is horizontal — which is what
 *    we want. Adding braces TOGGLES that, turning the cap line into a band across the top.
 * 2. The leading space is the empty field. The record parser trims it to nothing, which is the
 *    point; it must survive as its own field, so the `|` cannot be dropped.
 *
 * Graphviz has no sideways cylinder and never has: `orientation=` is documented as rotating POLYGON
 * shapes, and `cylinder` is drawn with beziers, so it silently ignores the attribute (graphviz issue
 * #2244, open since 2022 and still reproducible on 13.0.0). This is the closest native shape.
 */
export declare const QUEUE_SHAPE = "Mrecord";
export declare const QUEUE_LABEL_PREFIX = " |";
/**
 * Marker class stamped on every queue node. Graphviz copies `class` straight into the rendered
 * `<g class="node wp_queue">`, which is how runtime-visualizer.client.ts finds these nodes and
 * redraws them as true horizontal cylinders in the browser.
 *
 * A CLASS rather than an id prefix, because queue-kind EXTERNAL systems are queues too and share the
 * `system__` id space with databases — which must stay upright. Underscored, not hyphenated: DOT
 * emits a hyphen as `&#45;`, which is harmless but needlessly surprising to anyone reading the SVG.
 */
export declare const QUEUE_CLASS = "wp_queue";
/** Fill for the upright cylinder standing for an external DATASTORE (firestore, postgres, ...). */
export declare const DATABASE_FILL = "#E1F5FE";
/** Shape per external-system kind. Anything unrecognised falls back to the generic dashed box. */
export declare const EXTERNAL_SHAPES: Record<string, string>;
/** Fill per external-system kind, paired with {@link EXTERNAL_SHAPES}. */
export declare const EXTERNAL_FILLS: Record<string, string>;
/** Fill + border for the dashed terminal node standing for a system outside this repo. */
export declare const EXTERNAL_FILL = "#FAFAFA";
export declare const EXTERNAL_BORDER = "#9E9E9E";
/** Fill + border for the clock node standing for a scheduler-driven endpoint. */
export declare const CRON_FILL = "#FFF9C4";
export declare const CRON_BORDER = "#F9A825";
/**
 * The legend. Three columns — what a box IS, what a line MEANS, how to read a box — replacing the
 * three paragraphs of prose that used to restate the picture in words. Styled after
 * {@link GraphVisualizer}'s legend so the two graphs in this repo look like one tool.
 */
export declare function legendHtml(): string;