Custom Fonts
You can use any custom fonts in your applications. To do this:
Either attach or reference the font files in the Settings / Files tab. If you are referencing the files via URL make sure you have rights to do so otherwise they will not come across. I have run into situations where the fonts are set to not allow cross domain use. This is often the case with Font Awesome and other popular custom fonts.
Once attached or referenced the fonts will appear in your font options in the Style Editor.