What is a mobile first?
The time spent on mobile spent is catching up with desktops, tablet sales explode and while those of PC stagnated.
Result, mobile phones have become highly efficient and users hardly ever leaving their screen.
As mobiles take a more important place than the desktop computer.
The mobile first approach is to give priority to navigation, usability and site content for mobile, before adapting them to the web browsers on PC.
This approach improves the overall user experience of the site, which forces the designer to think simply, and effectively.
Simple proof: Social networks offer a simple and intuitive navigation inspired by mobile first.