Re: [css] min-height/min-width initials

The initial values of `min-height` and `min-width` are no longer `0`, now they are `auto`. Usually `auto` behaves like `0`, but not always.

Therefore, if you want to reset these properties, you should probably use `auto` and not `0` nor a theoretical synonym of `0`.

Anyways, I don't see how `none` would be useful. If you want to reset a property to its initial value but you don't know which is the initial value, you can always use the `initial` keyword.

- Oriol