(I retract my own vote on this, and downvote it instead)
I have made a larger version of the \(\lvert\uparrow\rangle\lvert\downarrow\rangle \) buttons in my old answer.
The entire image found in the theme actually occupies the same space, but I have removed the gaps between the arrows. Actually, that was not big enough either, so to make it "look" big, I made the arrow itself longer and wider, so it looks fatter and more noticeable. It actually looks pretty good, in my opinion.
Does it need to be a bit fatter or wider?
Of course, it is still very shabby, it's just a draft to get you all to understand what I am proposing. I will improve it if this design has the highest upvotes.
I've tried the \(\lvert\uparrow\rangle\lvert\downarrow\rangle \) but the result is too small. Here are the vote buttons:
Here's how it looks on the page:
(I purposely reversed my upvote on the question temporarily to illustrate vote buttons on unvoted (by you) questions)
I will try to make it look bigger, but I have actually made it as big as possible, I'll need to change the design.