Shoujo Vibes

D.N. Angel is an Anime adapted from a Shoujo Manga in-spite of the fact that it's a story with a male Protagonist with Hair that looks out of Shonen Jump and more then one female love interest.  

I however could tell it was Shoujo off it's first episode from it's hard to describe Vibes even though I know full well there are Shonen Manga based Anime with a high emphasis on Romance or even Romance being the main genre.  Shows like Rent-a-Girlfriend I like but I would not ever confuse with Shoujo.

Maybe you think I was prepared for this be Shoujo because of how it's like a Male Counterpart to Kamikaze Kaitou Jeanne and Saint Tail, but I'm also well aware of how this High School double life Phantom Thief genre started in the 80s Manga like Magic Kaito which was Shonen.

Thing is I have detected these Shoujo Vibes in Anime that turn out to not be Shoujo or even Jose Manga or Otome Games for that matter.

Shonen Manga based Anime like Blood+ and Karin have enough Shoujo vibes to make impossible that a Shonen Phantom Thief Manga could be this Shoujo.

But it is Shattered Angels that most surprises me when I see it classified as Shonen.  I've long memorized that it isn't officially Shoujo but I keep misremembering it as a Seinen.

Often the most Intense Shoujo Vibes are in Otaku Visual Novel adaptations like Rumbling Hearts and White Album, these are actually the Anime I'm inclined to recommend to people who loved Nana and want something with similarly great Melodrama.

Assassins Pride is a fall 2029 Light Novel adaptation that defies the usual Otaku Seinen vibes of that ecosystem to feel very very Shoujo.  It's so Shoujo that Mother's Basement hated on it.

And that's without even touching the messy debate of which Yuri are and are not legitimately Shoujo.