The reason most websites won't be optimized for 4K resolution is that very few people will be running 4K at 100%; that'd be incredibly tiny on a ~27" monitor. And even if people were running at that resolution, they'd only actually be using 4K if the app was fullscreened, which seems overkill on a resolution that high.<p>As an example, I myself am running 4K monitors scaled as 2560x1440, so there's no need for apps to optimize for 4K resolution, for me. Just high DPI.<p>If you're talking about optimising a web app you're developing, then you could use a bigger media query that targets 4K resolutions specifically, and handles it specifically. But I'd be surprised if you ever get anyone actually benefitting from that.
A client came to the company I work for, wanted a website and we built it for them.<p>They however complained at us ferociously because their website was 'completely broken' and unusable and did not fill the entire edges of their monitors.<p>I found this extremely odd and had to ask what monitors were they using.<p>The monitors:<p><a href="https://www.amazon.co.uk/Samsung-LC49RG90SSRXXU-Curved-Gaming-Monitor/dp/B08WWL7CC9" rel="nofollow">https://www.amazon.co.uk/Samsung-LC49RG90SSRXXU-Curved-Gamin...</a><p>We eventually had to account for very high dimensions and they still got irritated whenever their website did not fill the entire screen on these high dimensions. Media queries is what we used when we had to account for these sort of dimensions.<p>After the project was wrapping up, I got a bit curious and started researching home cinema screen dimensions just in case if this client was working from a home cinema screen and if I had to account for it or not.<p>Most people don't have 4K screens and sometimes it isn't worth it, but if you <i>really</i> have to support it, obviously prepare, conduct research and test on screens higher than your current setup in the chrome/ff dev tools.<p>Never again (for me working with that client at least)