Ranked FAQ?

i can't seem to find an FAQ on how the ranked system works. specifically, i am looking for information on how long one can go without playing a ranked game before LP starts to decay, and how many game in a "grace period", and if there are factors to determine the amount (in the grace period), if so, what are they.

if anyone can post a link directing me to that information, i would highly appreciate it. thank you.

here's a poll.