platform specific variants (mac:&)

[PeerRich]

we use tailwind + electron and I wanna have a variant for each platform:

<div className="mac:hidden">hidden on mac</div>

or

<div className="windows:px-4">padding 4 on windows</div>

discussion: https://twitter.com/peer_rich/status/1559659075759112193

potential solution: https://twitter.com/NFS__21/status/1559774502804156416