It occurred to me last night that J.K.Rowling's series is truly Gothic as well. The only difference being the substitution of a pre~adolescent male in place of the virginal post~adolescent female. Every other factor seems to be present. Allow me to run~down the list.
* dark, gloomy castle?
complete w/ resident ghosts, secret underground chambers, twisting stairs [literally];
* candlelight flickering or not at all?
Don't recall any electricity @ Hogsworth. Rightfully so, when they've got majik @ their fingertips!;
* extreme landscapes?
try the entire "campus";
* ancestral curses & omens?
ya think?;
* magic/supernatural?
at every turn of the page;
* a passion~driven wilfull villain/hero?
both;
* horrifying events or the threat of such?
every book in the series
The only two parameters that aren't met by Harry Potter are the "curious, fainting heroine" & "the hero whose true identity is revealed in the climax." We know who Harry really is by the end of Ch.1, Bk.I & he's been substituted for the fainting flower.