/**
 * Browser implementation of the platform seam (see host.ts for the contract
 * and host.node's counterpart). Substituted for `./host.js` when this package
 * is built for the browser; vite.config.ts wires the alias.
 *
 * There is no filesystem here, so:
 *
 *  - Mount roots are base URLs rather than directories, and `readMount` is a
 *    `fetch`. Containment is enforced by resolving against the base and
 *    checking the result still sits under it.
 *  - `readSource` can only read things that are actually addressable, i.e.
 *    absolute URLs. A browser caller naming a virtual path (`/main.ptx`) gets
 *    `undefined`, which means **`sourceContent` is effectively required** and
 *    `xi:include`s cannot be resolved from disk. Pre-resolve includes, or
 *    pass the merged document as `sourceContent`.
 *  - `assetsBase()` defaults to the version-pinned jsDelivr copy of this
 *    package, so an embedder needs no build configuration at all. Call
 *    `setAssetsBase()` to self-host.
 */
/**
 * Serve this package's `assets/` from somewhere other than jsDelivr — a
 * self-hosted copy, an offline bundle, a same-origin path. Must be called
 * before the first render; the compiled stylesheet is cached per root.
 */
export declare function setAssetsBase(base: string): void;
export declare function assetsBase(): string;
export declare function joinPath(root: string, child: string): string;
export declare function readMount(root: string, relPath: string): Promise<Uint8Array | undefined>;
export declare function readSource(location: string): Promise<string | undefined>;