Prayer: Must night prayers be done secretly and in the dark?

Practical Laws of Islam as per the teachings of Imam Khamenei

Prayer: Must night prayers be done secretly and in the dark?

English:

Question #715:

Is it necessary to perform the night prayers in the dark and in such a manner that nobody knows that we do it?

Answer #715:

It is not required to perform it in the dark or to hide it from others. However, it is not permissible to show it off.

-Imam Khamenei, Practical Laws of Islam, Importance and Conditions of Prayer