/**
 * Platform seam: everything in this package that touches the outside world.
 *
 * The renderer needs exactly three things from its host: read a file under a
 * mounted directory (the XSL tree), read a file the caller named by path (the
 * source, publication, docinfo), and know where this package's `assets/`
 * directory is. Under Node all three are filesystem operations. In a browser
 * they are `fetch`es. Confining them here is what lets the same renderer run
 * in both — see host.browser.ts for the counterpart, swapped in at build time
 * by vite.config.ts.
 *
 * Every read returns `undefined` rather than throwing when the target is
 * missing. Callers turn that into their own domain behaviour (mounts.ts
 * serves MISSING_FILE_STUB, xinclude.ts looks for an <xi:fallback>).
 */
/**
 * Read `relPath` (posix, leading "/") beneath mount root `root`. Refuses to
 * escape the mount: a `..` that climbs above `root` reads nothing.
 */
export declare function readMount(root: string, relPath: string): Promise<Uint8Array | undefined>;
/** Read a caller-named file (source, publication, docinfo, xi:include). */
export declare function readSource(location: string): Promise<string | undefined>;
/**
 * Serve this package's `assets/` from somewhere other than its own directory
 * — the programmatic equivalent of the `PRETEXT_HTML_ASSETS` environment
 * variable, which it takes precedence over. Must be called before the first
 * render; the compiled stylesheet is cached per root.
 */
export declare function setAssetsBase(base: string): void;
/**
 * This package's `assets/` directory.
 *
 * Computed with path functions rather than `new URL(..., import.meta.url)` so
 * vite's asset handling does not inline the file at build time. Works from
 * both src/ and dist/, which sit at the same depth in the package. The
 * overrides serve bundlers (the VS Code extension bundles this module and
 * ships the assets elsewhere).
 */
export declare function assetsBase(): string;
/** Join a child onto an assets-style root. */
export declare function joinPath(root: string, child: string): string;