When to change design from desktop to tablet and from tablet to mobile?

Question

Layout

There are 3 design options in figma, at 1440, 768 and 320px.
It is necessary, having them, to make a rubber layout, which, at some breakpoints, passes from one design to the next, on which breakpoints should this be done?
Because somewhere I meet that a tablet is <=768, somewhere >768 & <=1024 and I can’t come to something specific.

Answer 1

Works great for this:

@media (min-width: ---px) and (max-width: ---px) {
}

where "---" is the required permission

Answer 2

I think you were specifically given these permissions in Figma as breakpoints. So mobile up to 768, tablet up to 1440. Although to be honest it’s rather strange, then laptops get on the tablet