Haven't started reading yet, but judging from the style and apparently tragic ending, it really reminds me of Kaze to Ki no Uta...

That was the first yuri manga. We’ve come a long way since then.

This is missing the secret extra chapter where Resine wakes up from her nightmare about Simone dying and is then comforted by Simone, who is lying in bed next to her.

This chapter totally exists and I definitely did not make this up.