On prop-based styles (for extracted/compiled away values)

[kylpo]

I, personally, really like this API. But, I have recently felt that it may not be the best.

The problem with prop-based styles of compile-time, extracted primitives: they deceive the user. They aren't native props that may be dynamic. They're a different kind of prop, that doesn't really have a way to identify itself as different. [idea: maybe a new naming convention could help? _width={50} to denote a compile-away value? This way, the user would know to not have anything dynamic here.]

Consider css={``} instead, since folks are more used to this being a special prop?