QWebView not rendering all the website information

Question

I have a piece of code that renders an HTML file into a QWebView object.

This is the code:

    from PyQt5 import QtCore, QtGui, QtWidgets
    from PyQt5.QtWebEngineWidgets import QWebEngineView as QWebView

    # create web browser for the map
    app = QtWidgets.QApplication(sys.argv)
    frame = QtWidgets.QFrame()
    web_layout = QtWidgets.QVBoxLayout(frame)
    webView = QWebView()
    web_layout.addWidget(webView)
    url = 'map.html'
    this_path = os.path.abspath(os.path.dirname(sys.argv[0]))
    webView.setUrl(QtCore.QUrl.fromLocalFile(os.path.join(this_path, url)))

    frame.show()
    sys.exit(app.exec_())

The problem is that the QWebView object is not rendering the web page as it is:

QWebView rendering:

This is the correct rendering:

I'd like to know how to fix this.

This is the html file