Firefox OS Typeface
Designed to integrate with the character of the OS, the Fira Sans typeface also aims to cover the legibility needs for a large range of handsets varying in screen quality and rendering. When working with Fira Sans it is recommended that micro font sizes that fall below our guidelines are avoided.
Fira Sans Light
Fira Sans Regular
Fira Sans Medium
Fira Sans Bold
This is a list of the most common styles, and the basics you may need.
Note that the combination of sizes listed here are calculated for a 165 ppi screen. If you’re working with a different resolution you can use the conversion formula provided below.
|h1||Heading||2.5||11||Regular / 400||Headers|
|h2||Subheading||1.6||7||Regular / 400||Subheaders, Dialog titles|
|p.large||Body Large||2.3||10||Light / 300||Dialogs|
|p /ul||Body||1.9||8||Regular / 400||Body text, lists, default size|
|p.alt||Body Medium||1.7||7||Medium / 500||Med. body text and btn label|
|p.small||Body Small||1.5||6.5||Regular / 400||Status bar|
|p.mini||Body Mini||1.4||6||Regular / 400||Fine print and status bar|
|p.micro||Body Micro||1.3||5.75||Regular / 400||Application icon label|
Converting Type, Sizes in Point, Pixels and REM
The calculations are density dependant and you may switch from one pixel density to another to obtain the right relationship between points and rems.
This is the formula to convert point to rem depending on the device’s pixel density.
We use typographic points as a base for all our measurements, this was done as point sizes are universally understood in design and are locked to a physical measurement. Firefox OS currently reads type best in pixels, we convert our spec’d point sizes to pixels per resolution. Here is the formula we used:
|1 inch||=||72 point (pt)|
ZTE Open has 165 pixels per inch (ppi) = 72 pt
165ppi / 72 pt = 2.29167px (the amount of pixels in 1 point at device resolution)
I want my body text to be 8pt, how big would that be on a ZTE Open in pixels?
8pt x 2.91667px = 18.33333px
We want to round up, because bigger type is better. So 8pt is actually 19px on our ZTE Open device.
|10 Pixels||=||1 rem|
The Fira font family comes in a Sans Serif with 4 weights (light, regular, medium and bold) all accompanied by italic styles. The package also includes a Mono Spaced variant with 2 weights (regular and bold).