Especially for use in Firefox OS, Mozilla has developed a new font,
Fira , which is now available for free.
Fira is great for mobile devices with a small screen.
Comparing Meta Pro and Fira Mono (right) in the editor')
The font is available in several versions: the monospaced Fira Mono and the usual Fira Sans. For the latter, different bold faces have been created: Fira Sans Bold, Fira Sans Light, Fira Sans Medium and Fira Sans Regular, so that it can be conveniently used in headings / subheadings / text in the program interface.
Fira Sans Light

Fira sans regular

Fira sans medium

Fira sans bold

Examples of using

Recommendations on the use of font options in different elements of the interface, see
here .
Download font:Fira open typeFira True TypeFira Web FontPS The author of the font is Professor of the Bremen Academy of Arts and President of the International Society of Typographic Designers
Erik Spiekermann .