What is Kraken fee?

Could you please elaborate on the Kraken fee structure? I'm interested in understanding the different types of fees associated with using the Kraken platform for cryptocurrency trading. Are there any deposit or withdrawal fees? What about trading fees? Are they flat rates or do they vary based on the trading volume or type of cryptocurrency? Additionally, are there any hidden fees that traders should be aware of? I'd appreciate any insight you can provide on this matter.