I recall seeing a chost someone did where they had collapsible spoilers, but they were inline - specifically, activating the spoiler would cause the text to open naturally as though it was part of the paragraph (IIRC), rather than being its own whole drop-down separated awkwardly from the paragraph/sentence. I believe it was an inline version of the < detail > and < summary > tags, but searching for anything to do with CSS inline buries me in non-Cohost-relevant actual CSS/HTML stuff.
I cannot, for the life of me, find its usage, even though I distinctly remember liking the chost to save it for later. A fool I am for not bookmarking it.
Does anyone remember/know of this power?
EDIT: For anyone that stumbles across this, @easrng basically dunked it in one, and I didn't know enough about HTML to get even that, it's all in the comments.