[Edit] Per the comment below, the suggested feature is already possible via the custom theme creator (Appearance Settings > App Theme).
For anyone else looking to replicate Reddit's arrow colors, upvote on mobile is #ff4500, while downvote is #7193ff. Now that I'm trying it, I think I actually prefer the default due to the subtler contrast of the blue, but being able to change it is definitely a helpful option to have.
Something that I think has been missing from most Lemmy UIs is distinct upvote and downvote colors, versus the red upvotes and blue downvotes present on the standard Reddit interface.
Although I personally wouldn't feel the need to customize my upvote/downvote colors beyond that, given that others might want colors other than red and blue, I think implementing such a feature with an assortment of default colors customizable for each button would maximize its usefulness. Implementing it with a color wheel or a hex color input option would maximize options even further, though might not make for a very clean UI.
Thanks for implementing my prior suggestions! Have more suggestions on my list, but I'll keep to posting two at a time at most to let others have their share in suggesting ideas too. 👍
No problem! I absolutely love how customizable Arctic is. I've managed to make a bunch of not-so-nice-to-look-at themes and one that I really like a lot. It's great for someone like me who is constantly fiddling with settings (it's part of the fun!).