Option 1

Using fixed jumps to switch the whole page style based on screen size. This is not practical, but sometimes useful.

Screen sizes: https://screensiz.es

Option 2

Create breakpoints for individual parts of a page. We should start by designing for narrow screens first, and then resize the browser wider and pay attention to the point at which each part of the page starts to become unacceptable (that will be the breakpoint).

Source: Learning Web Design book.