// Base UI chooses useLayoutEffect only when `document` already exists at module
// load. Sheet and menu portals never attach if that check runs in bare Node.
// This module has to be the first import of any test that mounts those portals.
// The placeholder is only for that check and for libraries that inject a style
// tag while loading. The lifecycle harness replaces it before rendering.
if (typeof globalThis.document === "undefined") {
  type Placeholder = {
    nodeType: number;
    tagName?: string;
    childNodes: Placeholder[];
    parentNode: Placeholder | null;
    style: Record<string, string>;
    textContent: string;
    appendChild: (child: Placeholder) => Placeholder;
  };
  const make = (tag: string): Placeholder => {
    const node: Placeholder = {
      nodeType: 1,
      tagName: tag.toUpperCase(),
      childNodes: [],
      parentNode: null,
      style: {},
      textContent: "",
      appendChild(child) {
        child.parentNode = node;
        node.childNodes.push(child);
        return child;
      },
    };
    return node;
  };
  const head = make("head");
  const body = make("body");
  const documentElement = make("html");
  const document = {
    nodeType: 9,
    head,
    body,
    documentElement,
    defaultView: null as unknown,
    createElement: (tag: string) => make(tag),
    createTextNode: (text: string) => ({ nodeType: 3, textContent: text, childNodes: [], parentNode: null, style: {}, appendChild(child: Placeholder) { return child; } }),
    getElementsByTagName: () => [],
  };
  Object.defineProperty(globalThis, "document", { value: document, writable: true, configurable: true });
}