Why is Poloniex not working?

I've been trying to access my Poloniex account for hours now, but it seems to be down. I can't seem to log in or even access the website. Is Poloniex experiencing technical difficulties? Has there been an announcement about maintenance or an update that I'm unaware of? I'm getting worried because I have some important transactions pending and I need to access my funds. Can you shed some light on what's going on with Poloniex and when it might be back up and running?