What is the ruling on wearing a tunic that reaches the knees with tight trousers underneath, and is there any difference of opinion among scholars on this issue?

This dress, with the aforementioned description, is forbidden because it is tight and describes the body. The শরعي (Shar'i) dress must be loose and flowing, neither describing nor transparent. Violating these specifications is tabarruruj (displaying one's adornments), which is one of the major sins. It is not permissible to obey one's mother in wearing this type of clothing, as it is disobedience to the Creator.