Where to buy bitcoin in Russia?

As a cryptocurrency enthusiast, I'm curious about the options available for purchasing bitcoin in Russia. Could you elaborate on the various platforms and methods that Russian citizens can utilize to acquire bitcoins? Are there any specific regulations or restrictions that one should be aware of before engaging in such transactions? Furthermore, how do the exchange rates and fees compare to other regions, and what are some of the most trusted and reliable sources for bitcoin purchases in Russia? I'm particularly interested in understanding the steps involved in the process, as well as any security measures that should be taken to safeguard one's investment.