This might be some kind of a weird requirement for a piece of art, but I would literally never expect a website to center a div according to the browser window instead of the viewport. It just looks wrong and feels wrong.
While the Silicon Valley is merely a figurative Mecca for all things tech, Apple could require people to be facing Cupertino if you want to watch a WWDC stream :D
(And yes, CSS can rotate around all three axes, so you could make a div that resists rotating your device in addition to resisting translation...)
Sometimes there is no size setting that will get the text lines on a page to fit horizontally without making the text too small to read. Making it large enough to read means lots of left and right scrolling which is annoying.
A mode where moving the phone sideways scrolls the text at a matching rate so that the experience is similar to reading a page with a magnifying glass might be handy.
Wrapping is fine on some material, but when there are tables it can be very annoying.
[0]: demo: https://mdn.github.io/dom-examples/screenleft-screentop/
My tiling window manager doesn't care what your snowflake app thinks it wants, and I don't either.
I'm trying to think of any that try to fight the interface quite as much as this.
Yes, some things in some complex applications can break, but there are solutions and, practically, these particular things you listed simply aren't among those that break.
The result is that you can't open open two file property dialogs at once (to compare sizes or dates or any other meta data, it's a common thing one might want to do).
Hopefully you'd agree that Wayland should allow apps to position windows relative to their own windows, at the very least.
It's a design choice.
If you do have that attitude there are a million other OOP style things to throw out for speed and correctness before virtual monitors and coordinating compositors
That's an awfully big assumption. For starters, you're assuming that the browser window itself is centered on the screen, and that the device is centered in front of the user.
I don't think this is the point of centering an element horizontally at all, and the result you have created here is not at all what I as a user want.
Guess they think like the OP.
PS: if you switch from the touchpad to a wireless mouse, we'll move the div accordingly
2. The demo doesn't even work, the div stays centered in the viewport, not the program window when I open a side bar (Firefox).
3. Rarely does my browser even cover the center of my workspace, so it would be impossible to center anything in the center of my view without forcibly moving the program window from within the website.
The same way the vertical centering counts the viewport height only, not the url bar and the tab bar.
Anyone got a Tampermonkey script or tiny extension to re-override this to make such sites actually center in the viewport, like I prefer?