I'm trying to develope a website with the responsive design and I know that I have to use media queries, I used them and they work fine on my desktop (When I resize the window the look change). So I was wondering if there are some 'standard values' to use them with smartphones/tablet/desktop. I've looked at other questions but are too old.
A bit of searching on CSS a you may found this :
http://getbootstrap.com/css/#grid-media-queries
/* Extra small devices (phones, less than 768px) */
/* No media query since this is the default in Bootstrap */
/* Small devices (tablets, 768px and up) */
@media (min-width: @screen-sm-min) { ... }
/* Medium devices (desktops, 992px and up) */
@media (min-width: @screen-md-min) { ... }
/* Large devices (large desktops, 1200px and up) */
@media (min-width: @screen-lg-min) { ... }
Basically (if you read the comment lines), for classic CSS (meaning no less/sass), you would replace @screen-sm-min by 768px for instance. Or whatever fits you.