Janan: Why does mania have such a long face?
Viki: I don’t have the foggiest idea.
So please explain the meaning of “Have such a long face” and "The foggiest idea" ?
A “long face” means a sad face.
“I don’t have the foggiest idea,” or, “I don’t have the foggiest notion,” means, “I don’t know at all.” It means the person doesn’t have even vague, nebulous knowledge about something.