I'm gonna try pointing to the relevant CSS, but be warned, I am not a CSS wizard. I am also probably not a smart man, posting about CSS on HN while not being a wizard.
The relevant classes seem to be .sidebar, .sidebar-toggle, .motion-element, and .posts-expand, the last of which seems to control the transforms and durations. This is where my knowledge breaks down, since I'm not sure how they .sidebar or .motion-element trigger .posts-expand or any of the other animation CSS. Hopefully someone can help fill in the rest!
¯\_(ツ)_/¯
Three quarters OT, but I really don't.
Yet another ill-informed, misguided piece of flashy form before content. I have given the text a miss. I generally do if it can't be arsed to show itself without a load of js trickery.
