IcedRaktajino

Awesome! Yeah, spoilers aren't standard markdown (AFIAK) and most apps just copied the way lemmy UI implemented them as custom containers.

At least in the default UI, it's still not working right. It's all treated as the title of the spoiler.

Most clients require it as :

Title that shows when collapsed
The rest of the text that should be hidden in the collapsed part.

More text that should be hidden.

Not sure what client you're using, but the spoiler tag not being closed causes them to not work.