How does permission work on phones and desktops?

Question

iPhone

Hey!
Can you please explain how screen resolution works? I can't understand, for example, the iPhone Plus has a resolution of 1920x1080 with a 5.5" display, while on my laptop it's 1440x900 with a 13" diagonal, how can I understand this?
Let's say I want to make three blocks in a row on desktops, and if the screen width is < 480px, they will be displayed under each other, that is, I will corny write media (max-width: 480px) {...}, does this mean that on an iPhone will they also be displayed in a row and, obviously, will not fit into it? Also interested in the question, if I want to watch a movie on iphone plus, will it be optimal for me to download movies with a resolution of 1080p?
PS I understand that the question is most likely idiotic, but I would like to understand it :)

Answer 1

Screen resolution is specified in pixels - light-emitting units that can change color. It does not depend on the screen size - small smartphones (5 ") are already stuffed with displays with a resolution of 3840 x 2160, while in large 15" laptops HD (1366 x 768) and FullHD (1920 x 1080) dominate.
This is partly due to Windows' poor scaling support over the years, weak graphics cards that can't handle high resolutions well, and the cost of producing large displays.
What matters to you when creating a website or application is the horizontal screen resolution (the phone is usually rotated vertically) and DPI (the number of pixels per inch). Based on the DPI, you will be able to determine what size the real screen is and how you should arrange the blocks and elements. There are other ways to determine the mobile client, the essence is the same, to determine that you have a phone in front of you and change the design accordingly. Sharpening exactly to the screen resolution is a bad idea, on a modern 5 "phone with 2K resolution everything will look very small.
As for movies, you need to pay attention not only to the resolution of the video, but also to the quality of the compression. At a low FullHD bitrate, the video will look worse than 720p quality. In short, choose by file size. If your phone is capable of 1080p download it. If you don't want to wait too long for a download, 720p is also fine, on a small screen it's harder to notice the difference.