N4
〜でも 〜でも
Whether ~ or ~, Neither ~ nor ~
これでも、それでも、何でもいいです!
This, that, anything is fine!
Explanation
「AでもBでも」 means 'whether A or B …'. Two options are set side by side, and the result is the same either way.
1Affirmative, either is fine, often with 「いい」 or 「大丈夫」: 「今日でも明日でも構いません」 (Today or tomorrow, either is fine), 「肉でも魚でも、何でも食べます」 (Meat or fish, I'll eat anything).
2Negative, neither works, with a negative ending: 「大人でも子供でも解けない問題」 (a problem neither adults nor children can solve).
Mixed up with
Forms: nouns and な-adjectives take 「でも」 directly: 「簡単でも複雑でも」. い-adjectives change to 「くても」: 「寒くても暑くても」, never 「×寒いでも」.
Unlike 「とか〜とか」, which just gives a few examples, 「でも〜でも」 says it makes no difference which one, and you don't mind.