What chain is CSPR on?

Could you please elaborate on the blockchain technology that CSPR, or Casper, is built upon? I'm curious to know if it utilizes a proven and secure consensus mechanism, or if it has adopted a unique approach to ensure the integrity and scalability of its network. Additionally, I'm interested in understanding if CSPR's chain is interoperable with other blockchain networks, enabling cross-chain transactions and increased functionality. Clarifying these details would help me better assess the potential and use cases of CSPR within the cryptocurrency and finance landscape.