2560x1440: "a common resolution in the gaming monitor market, and it's an affordable alternative to going full 4k."
3840x2160: "full 4k or Ultra HD. While 4k usually reserved for higher-end PCs now, prices are falling, graphics technology is improving, and demand for 4k is being driven by the TV market, where it's much more common. It's safe to assume that over the next few years, 4k will easily overtake 1080p as the de-facto standard, so it's definitely worth accounting for 4k now."
Above 1920px, multiply base font-size with 1.333 (4/3)
Above 2560px, multiply base font-size with 1.5 (3/2)
Motivation: See https://css-tricks.com/optimizing-large-scale-displays/
We need to enlarge
font-size, as we did at 728px.We target the following screen dimensions (source: https://www.lifewire.com/page-sizes-based-on-monitor-resolutions-3469969):
Above 1920px, multiply base font-size with 1.333 (4/3)
Above 2560px, multiply base font-size with 1.5 (3/2)