How Phemex works?

Excuse me, could you please explain in more detail how Phemex operates? I'm particularly interested in understanding their trading platform, the types of cryptocurrencies they support, and any unique features or advantages they offer compared to other cryptocurrency exchanges. Also, how do they ensure the security and safety of their users' funds and transactions? And lastly, could you elaborate on their fee structure and any promotions or discounts they might offer to traders? Thank you.