If you prefer to use a classic font like Arial instead of the system font or if you experience some problems with the system font in Piwik 3 install this theme.
How do I activate this theme?
Once you have installed and activated this plugin, go to "Administration => Plugins => Themes" and there you can activate it.
Will all users of my Piwik installation use this theme once activated?
Yes, in Piwik an activated theme always applies to all users.
0.1.0 Initial version