qss file in config directory and add StyleSheet tag to config. This learning track starts from scratch, assuming no prior knowledge of GUI concepts. This download includes both the Qt framework and Qt Creator which is the native Integrated Development Environment (IDE) for Qt.
This Python Qt tutorial shows how to create a (working!) chat client for Windows, Mac or Linux. Qt installer framework tutorial What is PyQt5? PyQt is a library that lets you use the Qt GUI framework from Python.