SVX (Yekaterinburg) - PEK (Beijing) - HkG (Hong Kong) - SEA (Seattle)

I'm a Mexican Citizen that lives in USA. I have a flight from Russia to Beijing, and I will stay 3 hours layover in route to Hong Kong. I will stay in Hong Kong for 52 hours to visit. Then, I have my final flight from Hong Kong to Seattle, Washington.

I'm very worry that I have bought tickets without realizing that I might need some type of Visa to enter Beijing. Do I need a transit or travel entry permit prior to boarding my plane in Russia?

Please help!