Max-witdh issue and inconsistencies

[g1franc]

- Do you want to request a feature or report a bug?
Feature

- What is the current behavior?
There is a max-width that is limiting to 80 col rules from the eighties. Thanks for the user with wide-screen. Therefore at some resolution, the limit change more to 120 col limit which is way better.

- What is the expected behavior?
Don't limit the max-width. User can use the "Reading mode" of their browser if they want to have a 80 col style.

- Please mention your operating system version and the version of your browser
Windows 10, Firefox Quantum.