This lesson describes “although” and “even if” as “similar” but states that “although” is “more elegant and subtle” than “even if.” This is not quite right. There is a significant difference in meaning. “Although” is usually followed by a concession/affirmation of fact, while “even if” is followed by a hypothetical assumption (without a concession/affirmation of fact).
“Although I stole the hat, I did not deserve the death penalty.” — I am admitting I stole the hat.
“Even if I stole the hat, I did not deserve the death penalty.” There is ambiguity here. I am not necessarily admitting I stole the hat. I am saying that, even assuming I stole the hat, I don’t deserve the death penalty.
It’s unclear to me if there is a similar distinction in meaning in French between bien que and meme si which explains why one form takes indicative and the other subjunctive. I would expect the version that is closer to although and which affirms a fact to take indicative, and the other subjunctive. At least that is how it works in Spanish - “aunque” with indicative is “although,” and “aunque” with subjunctive is “even if.”