Explain the principles of the CAP theorem and its significance for distributed systems.

The CAP theorem states that in a distributed system, it is impossible to guarantee all three properties simultaneously:

• Consistency — all nodes see the same data at the same time.
• Availability — every request receives a response (successful or error).
• Partition tolerance — the system continues to operate despite network splits.

In the event of network partitions, the system must choose between consistency and availability. This is important for designing distributed systems, as it helps determine trade-offs: for example, databases can be either strictly consistent but with potential delays (CP), or always available but with possible temporary inconsistency (AP).