What is Responsive Web Design?

No one doubts today that the use of smartphones is exploding. More and more people are now visiting websites from their mobile browser. On the Zero site, more than 5% of visitors come from a mobile device. They were half (2.5%) a year earlier.
The site statcounter.com shows eloquent curves in relation to the evolution of the mobile compared to the desktop computers:

Evolution of the use of computers and mobiles
Do you have a site where you plan to make one? You’re probably wondering “How can I make my site mobile?”.
More and more people are talking about responsive web design, which seems to be a magic solution to this problem … but what is it concretely? How do you make a site in responsive web design, is it hard, is it suitable for all sites? This tutorial gives you a short introduction to the subject so that you can decide if you will make your next site in responsive web design … and how you will have to do it.
A site devoted to mobiles: a false good idea?

When one sees that there are more and more people who go on the web from their mobile, the first reflex is in general to say:
But it’s simple! I just have to make a site dedicated to mobiles! No ?
That sounds sensible. After all, many sites have already done so. They have :
• The main site, for computers (eg www.lemonde.fr)
• A mobile site, for mobile devices (eg mobile.lemonde.fr)

However, there is a problem that obviously appears: it makes 2 sites to create, and therefore 2 sites to manage.
Another problem has arisen over time, a little less obvious to see that coming: other devices are born, at the border between mobiles and computers. I mean, of course, the tablets. Are you going to make additionally a third special tablet site?
Wait, as if that were not enough, there are now large format smartphones, like the Galaxy Note, halfway between the smartphone and the tablet. And tomorrow, who knows what other device will appear? Maybe a very large screen? The connected TV?

To the rescue, there are too many different mobile devices!
Are you sure you want to create multiple websites? No, what you want is to create a site that everyone can visit, both people who come from a computer and those who come from their mobile, tablet or whatever else.
It is clear that making a site dedicated to mobiles does not hold, because there are too many mobile devices with different sizes on the market. Rather than running out of steam to manage multiple sites, the creators of websites began to imagine a solution that would manage all these devices … all at once. This solution has taken the name of responsive web design. What is it ? This is what we will see now.