How to make mobile web version?

Question

I just learned about css responsive , but I realize that when I visited mobile web page and pc web page, the site has different layout. do they make two version or just only use responsive page using css media query?
and what is mobile jQuery?

Answer 1

At the bottom of your current CSS, add @media query selector.

eg.

#box {
margin: 10px;
}

@media only screen and (max-width: 767px) {
/* add your mobile view CSS here which overrides the current CSS */
#box {
margin: 5px; /* this overrides the default 10px value, makes 5px margin for screen size smaller then 767px mobile size */
}
}

Answer 2

Calviղ but you can see that nav bar layout of mobile web is different with pc version.
and the link is m.website.com in mobile and website.com in pc