I will spare you the drama and get right to it. SharePoint forces IE8 mode via this tag in the master page:
If you are trying to use web fonts with SharePoint 2010, you are likely having an issue getting them to display. That tag above is the reason.
If IE8 is a requirement, then you’ll need a new solution. Otherwise, change the IE8 metatag to Edge. Edge defaults to the most recent version.