Clean up styles

I've begun the work of making the implementation of style methods more uniform and correct, but this got to be so big that I decided to stop half-way.

This PR will represent "cleaning up" `arc` - `list_box` (using the list in #711).

I'll make lots of inline comments on what I considered "cleaning" and I'm eager to hear feedback.
I'm having elements call on `@style` instead of `style` since `style` runs through a few methods before returning @style.