On Fri, 24 Apr 2015, Idris Samawi Hamid ادريس   سماوي حامد wrote:

>  \definehighlight[emphasis][style=\em]
>...
>  Some \emph{emphasis} and \important{important}.
>
>  The exported formatting of \emph vanishes in each instance.

You define \emphasis but use \emph.

Aditya