I like working with dark theme because the strain on the eyes is much lesser and also that I can work late night if needed with just a simple table lamp. Its wonderful btw to work at night or early in the morning. Here is what my setup looks like.
Now coming to the point, here is what you need to do to enable dark theme in your jupyter notebook.
Install the jupyterthemes library through pip.
pip install jupyterthemes
Enable the dark theme using the below command
jt -t <theme-name>
List of themes are :
I personally use the below configuration.
jt -t monokai -f fira -fs 13 -nf ptsans -nfs 11 -N -kl -cursw 5 -cursc r -cellw 95% -T
More details about the various options can be found here: https://github.com/dunovank/jupyter-themes