How do I change the font size of code output in a Jupyter Notebook within the notebook itself?

Question

I have a set of Jupyter Notebooks that I store on GitHub so that users can access them through Binder.

I would like to reduce the font size of the output of code blocks for the user. All information I can find on changing the font size, including on Stack Overflow, relates to changing the custom.css file. This file changes what I see in my own browser, but it is not part of the repo, cannot be pushed to GitHub, and is not served by Binder, so altering this file does nothing for what my users see.

Is there a way to change the output font size that's native to the notebook itself and would therefore survive being channeled through GitHub and Binder?

This is Jupyter Notebook 5.4.0.

Answer 1

Add this to all notebooks as the LAST cell. Because javascript used the users must have trusted the notebooks.

%%javascript
$('.output_result').css('font-size', '5pt')

Answer 2

Users should be able to change the font size according to their visual capabilities. Give users the instructions to install jupyter_contrib_nbextensions and to enable the Code Font Size extension: https://github.com/ipython-contrib/jupyter_contrib_nbextensions