Dark Theme ... IDLE, QT console

[#1]

If you need it and are using ArcGIS PRO.  Just make a desktop shortcut, then theme away

Just change C:\arc_pro to your installation path

Similarly for Jupyter QtConsole...

Target: C:\arc_pro\bin\Python\envs\arcgispro-py3\pythonw.exe "C:\arc_pro\bin\Python\envs\arcgispro-py3\Scripts\jupyter-qtconsole-script.py"

Start in: C:\arc_pro\bin\Python\envs\arcgispro-py3

Then select View, Syntax Style... there are a couple there