src/app/upload/components/Portal.js

// Portal.jsx
// Renders children directly into document.body, escaping any
// parent overflow / transform / stacking-context restrictions.

"use client";

import { useEffect, useRef } from "react";
import { createPortal } from "react-dom";

export default function Portal({ children }) {
  const elRef = useRef(null);

  if (!elRef.current && typeof document !== "undefined") {
    elRef.current = document.createElement("div");
  }

  useEffect(() => {
    const el = elRef.current;
    if (!el) return;
    document.body.appendChild(el);
    return () => {
      document.body.removeChild(el);
    };
  }, []);

  if (!elRef.current) return null;
  return createPortal(children, elRef.current);
}