Highlight Selected Text inside a Jupyter Python Cell

On my Jupyter Notebook, I am not able to get Selected Code lines highlighted. I have searched and tried CSS suggestions from Stack Overflow etc. But so far no avail.

I can get selected Text highlighted in Output and Markdown areas. But not in Code Cells.

Appreciate any tips:

a) The correct location of CSS file that is being used.
b) The CSS style element and its properties.

Thanks in advance

Sri.
P.S. I am still running 2017 version. I have tried to stay away from Upgrading Anaconda or Python as many libraries/code used to break whenever I upgraded. Things I exercise are Speech Stuff, Audio/Midi Stuff, Image/Graphics Stuff, UI/Widgets etc…

Below is the cut-n-paste from the Jupyter Notebook “About” text.

About Jupyter Notebook

Server Information:

You are using Jupyter notebook.

The version of the notebook server is 5.0.0 and is running on:

Python 3.6.1 |Anaconda 4.4.0 (64-bit)| (default, May 11 2017, 13:25:24) [MSC v.1900 64 bit (AMD64)]

Current Kernel Information:

Python 3.6.1 |Anaconda 4.4.0 (64-bit)| (default, May 11 2017, 13:25:24) [MSC v.1900 64 bit (AMD64)] Type “copyright”, “credits” or “license” for more information. IPython 5.3.0 – An enhanced Interactive Python. ? → Introduction and overview of IPython’s features. %quickref → Quick reference. help → Python’s own help system. object? → Details about ‘object’, use ‘object??’ for extra details.