Firefox OS typeface, Fira Sans, has been made available for free download and use on Mozilla’s site as part of their style guide with some handy recommendations, text styles and usage examples.

The Fira font family is a sans serif and comes with four weights (light, regular, medium and bold), also available in italic. It also includes monospaced variant with two weights (regular and bold). Free downloads include: Fira Open Type, Fira True Type and Fira Web Font.