What is the fee for pendle?

Could you elaborate on the fee structure for Pendle? I'm particularly interested in understanding if there are any transaction fees involved in using the platform. Additionally, I'd like to know if these fees are fixed or variable, and if they depend on the amount of trading activity or the type of transaction. Understanding the fee system is crucial for making informed decisions as a user of Pendle's services. Could you provide a detailed breakdown of the fees associated with using Pendle?