What is the correct posture for sitting in university classrooms in mixed-gender settings, and is it permissible for male and female students to converse under the pretext of companionship or academic exchange?

There is no harm in men and women being in one place if everyone adheres to the Sharia guidelines, such as hijab, absence of khalwa (private seclusion), and lowering the gaze, with preference given to the separation of study areas for male and female students. A man addressing a non-mahram woman or vice versa is not permissible except out of necessity, with the woman adhering to hijab, not speaking in a soft alluring manner, and ensuring there is no khalwa, because speaking under the pretext of collegiality or academic exchange is from the whispers of Satan.