I think debating where the breakpoints should be is fair. My rule of thumb is that a site should not go to “tablet” mode until it’s below half the width of a la

I think debating where the breakpoints should be is fair. My rule of thumb is that a site should not go to “tablet” mode until it’s below half the width of a laptop monitor: ie anyone on a laptop should be able to put two windows size by size and still see the “full-width” version. However, this is impossible to actually implement, because we don’t get media queries in “what percentage of the screen is visible,” we just get how many pixels (or virtual pixels) we have to work with. One variation on the authors idea: suppose that browser vendors implemented media queries differently so they provided “screen=small|medium|large|xlarge”. Then the widths which trigger these layouts could be configured in the browser (with sane defaults), and the user could “lock” their browser to whichever query they preferred regardless of the window size. But, that would actually be really hard to deal with on the implementation and testing side. Do you - should you? - care if a user has their browser locked to “xlarge” but then the layout breaks when the window is shrunk down to 500px wide? At the end of the day there’s no perfect solution here.