Thanks, looking at a few CSS frameworks I think I've been confused that they seem to have coarse resolution break values and I thought this was an anti-pattern

Thanks, looking at a few CSS frameworks I think I've been confused that they seem to have coarse resolution break values and I thought this was an anti-pattern ("don't detect mobile with a hard-wired resolution"). Maybe my mistake is to confuse resolution (after all modern phones often have equivalent resolution as many desktops) with width, so mobile is portrait, desktop often landscape. Instead of a mobile type presentation and a desktop type presentation just go with say one column if <600px or something, two columns if more and not worry if it's a mobile device. Maybe that's what the CSS frameworks are actually doing.