WARNING: This script can cause errors in Google Drive. If using Stylus, it is STRONGLY RECOMMENDED that you apply to URLs matching the following RegExp (it applies to every URL except docs.google.com):
This style removes all traces one of the worst fonts of all time, Arial, and replaces it with the similar but better looking font Helvetica. Arial was designed to be "metrically compatible" with Helvetica, which basically means the two fonts' characters take up the same amount of space. This and their similar appearances mean that the fonts can be substituted for each other without problems.
For more anti-Arial propaganda, see https://www.marksimonson.com/notebook/view/the-scourge-of-arial
This script really only works on Mac, because 99% Windows and Linux PCs don't have Helvetica installed, and even if they do, their (bad) font renderers make it so Arial actually looks better than Helvetica on those systems.
Tested on the following configuration:
TIP FOR FIREFOX USERS: for better performance, I recommend going to Preferences -> Fonts and Colors -> Advanced and setting "Proportional" to "Sans Serif". This decreases the chance of the page being set in Times on poorly programmed webpages.
Licensed under CC0 public domain dedication: https://creativecommons.org/publicdomain/zero/1.0/