Is it allowed to bath shower in the completely closed bathroom naked? (For men and women).

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
It is lawful for the Muslim to make Ghusl naked in a bathroom or in any place where nobody else could see him. This is the opinion of the majority of the Muslim scholars. Among the evidence for this we can mention the story of Prophet Moses (Peace and blessing be upon him) who took a bath naked and that of Prophet Ayub (Peace and blessing be upon him) who also took a bath while naked. These two stories are related in sound Hadith by al Bukhari. There is nothing in our Shariah that contradicts the mentioned acts of these two Prophets. So, this act taking a shower naked is lawful for Muslims.
Allah knows best.