Cannot print text files from the GitLab interface

Summary

Cannot print text files from the GitLab interface.

Steps to reproduce

• Navigate to a text (plain text, markdown, etc.) file on GitLab. An example file.
• Try and print the file (File > Print, or ⌘P).
• The print preview displays a blank page.

Expected behavior

• The contents of the text file should be printed (and be shown in the print preview).

Relevant logs and/or screenshots

Possible fixes

• This is probably a problem with the print stylesheet.