I've used vh/vw a bit, and the new fr unit (which is useful when working with CSS Grid).
I've also come across the new (I assume that they're new) units vmin and vmax, which works pretty much the same as vh and vw. But represents the bigger/smaller side of the viewport instead of the height and width.
It'd be quite interesting to see a use case for all of these units.
vmin and vmax are actually as old as vw and vh, both on Level 3. Not many use cases, but there are some! They're especially useful for responsive layouts and font sizing.
Some trivia about them:
calc(15vw + 15vh - 15vmin)
They're great units, unfortunately they lose a lot of value due to inconsistencies among mobile browsers (I'm looking at you, Safari).
I used to like vh/vw. Until I discovered that Safari scaled them with zoom. So if you are zoomed at 85%, 100vw becomes 85% of the width of the page which is now equal to 72.2% of its original size.
I don't know who thought that made any sense and it seems to be the only browser that behaves that way :\
Oh, I see.
It's a shame that it's not implemented consistently, which often seems to be the case with CSS.
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