Why do girls wear alluring clothing these days, what is the ruling on such girls, and were they like this in the past?

It is forbidden for Muslim women to imitate Jews and Christians in immodest display (tabarruj) and unveiling, and in appearing before non-mahram men in short, transparent, or body-revealing clothes. Allah has obligated women to cover their 'awrah (private parts), and not to display their adornment except to their mahrams and husband. He commanded them to draw their cloaks close around them and forbade imitation of disbelievers.

The Prophetic hadiths have indicated the prohibition of tabarruj and dispraised those who engage in it, such as his (peace and blessings of Allah be upon him) saying: "Two types of people among the inhabitants of Hell I have not seen… women who are clothed yet naked, inclining [to evil] and inclining [others] to evil, their heads like the humps of leaning camels. They will not enter Paradise nor smell its fragrance." And his saying: "Whoever imitates a people is one of them."

The women of the Companions adhered to hijab and modesty immediately upon the revelation of the verses, tearing their cloaks and veiling themselves with them, and went out as if there were crows on their heads due to their coverings.