How can I stop getting logged out of icloud mail every time my PC goes to sleep?

Is there a way to stay logged in on icloud mail when using Windows? I keep a dedicated tab for my icloud mail in my browser, but every time my PC goes to sleep, I get logged out. I want to stay logged in indefinitely; is there a way to do that? Obviously I'll be logged out if I close the browser or power off my PC, but aside from that, how do I keep from getting logged out? It's quite irritating, and time-consuming, to have to go through the process so often.