Rent your self a radiator pressure tester from one of your local auto parts stores. Pressurize your system and you'll find the leak.I spoke to 3 dealers and only 1 was willing to check the vin and said that there’s no service bulletin for a 2011 Civic. Since all of them are asking for. $150+ inspection fee, I don’t think it’s worth going to a dealership.
Also, I didn’t see any froth in the oil cap or fuming gas under the hood which would suggest a head gasket blow up. Nothing is leaking from the exhaust as well.