How to hide the emoji "message reactions"?

I’m trying to figure out how to remove the recently added emoji reactions to posts. I don’t care about them, and each one moves the next post down a little, wasting screen space.

I can do it in ublock origin with the filter:
quokk.au##.message_reaction

So I tried to modify the CSS from this post’s example .fe-warning { display: none; } into .message_reaction { display: none; }. But that doesn’t work, and I’m a little lost where to go from here (I don’t really know what I’m doing in the first place). Thanks for any help!