Good responsive design is _hard_. I think people tend to pave over this by just recommending "mobile first" and then giving a list of breakpoints named suggesti

Good responsive design is _hard_. I think people tend to pave over this by just recommending "mobile first" and then giving a list of breakpoints named suggestively after device classes ("iphone", "tablet", "notebook" and so on). There's sadly no easy, widely supported, reliable way to identify what designers try to deduct from these breakpoints. Even if you correctly identify my 4K screen as a notebook, that doesn't mean you'll take into account that it has a touchscreen. And even if you detect the touchscreen, I may prefer using the trackpad instead. Microsoft had the right idea with the prominent touch/mouse toggle on their Office desktop apps, even if the solution feels a bit clunky and awkward. In the end you'll probably just need to take an educated guess and allow the user to override. But sadly this means instead of a simple linear progression from lowres/touch to hires/mouse, we end up with a multi-dimensional matrix of touch/mouse, lowres to hires and so on, doubling or multiplying the variations with each new variable (e.g. dark mode).