/**
 * `@font-face` CSS with the font files inlined as data URLs, for markup that
 * is rasterised as a standalone SVG image (mermaid diagrams): an SVG drawn
 * through `<img>` cannot reach the page's web fonts, so any family it names
 * must travel with it.
 *
 * Walks document stylesheets for matching `@font-face` rules and inlines
 * their `url()` sources. Results are cached per family set; a result without
 * inlined data (stylesheet not parsed yet, font fetch failed) is not cached
 * so the next capture retries.
 */
export declare const normalizeFontFamily: (family: string) => string;
/** Families the document declares via `@font-face` (loaded or not). */
export declare const declaredFontFamilies: () => Set<string>;
export declare const fontEmbedCssFor: (families: readonly string[], _host?: HTMLElement) => Promise<string>;
/** Drop cached CSS so a later capture retries stylesheet reads. Tests only. */
export declare const resetFontEmbedCssCache: () => void;
/**
 * Inline every declared web font an SVG names into a `<style>` at its top,
 * so the diagram paints the same through `<img>` as it does in the DOM.
 * Families the document does not declare (system stacks, generics) are left
 * to the renderer.
 */
export declare const embedSvgFonts: (svg: string) => Promise<string>;