Does the religion obligate a girl to work to earn a livelihood, especially if she is in financial need and has no provider? And is it permissible for her to work in mixed-gender environments if she preserves her modesty?

Mixed-gender work is forbidden if it leads to a forbidden religious act, such as being alone with a non-mahram man (khalwa) or not observing hijab, especially if it is possible to find non-mixed work. This is based on Allah's saying: "And do not exchange the bad for the good" (Quran 4:2) and "Say: Not equal are the wicked and the good" (Quran 5:100). However, if the forbidden elements are removed and there is no alternative, then there is no harm in it.