there are still a lot of problems with using rem on pc. I think there are these points

1. compatibility, PC compatibility requirements are still quite high
2. calculation, rem as a unit requires a simple calculation
3. the size of the PC browser will change, and each change will need to reset the size of the font
4. fonts on pc cannot be determined by browser size (Google has a limit on minimum font size), and pc adaptation is mainly about width, rem adaptation is all,

so pc adaptation is more suitable for grid system, and rem or mobile terminal is more suitable

is that rem is a relative unit, and it is impossible to fully match the design draft. The final rendered element will have a pixel difference (possibly)

you can take a look at the explanation of Tencent team http://imweb.io/topic/5745adf.
. Generally speaking, multiple adaptation solutions coexist with vw vh rem 100%

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