fix the size of the spoiler tag

[fbtw]

Fix the size of a post with a spoiler tag before been opened when the text is longer than the spoiler tag
The problem with the blank space of the tag having the same size as the final text is some instances allow thousands of characters and the tag can occupy several pages of timeline.

Before:

After:

[grishka]

It is intended that the spoiler is the size of the text it hides.

[sk22]

then there should be a maximum height imo, see #166

[waldyrious]

then there should be a maximum height imo, see #166

Alternatively, the spoiler could be positioned in a way that keeps it on-screen at all times — e.g. using sticky positioning, where it is centered when possible, but sticks to the top or bottom of the visible area if the post is too long and its center would be off-screen. This way the current effect of the spoiler area being the same size as the text it hides, as @grishka mentions, would be preserved.

[Gargron]

Max height is what we do in the web app, that would be acceptable.

[GPHemsley]

It is intended that the spoiler is the size of the text it hides.

Why?

[grishka]

I'm closing this because spoilers in the Material3 redesign have a fixed height and expand into additional display items when revealed, making this issue irrelevant.