- remove depth indicators as not needed now that comments layers are clearly defined

- new comment classes .downvoted and .revealed to have more precise CSS selectors
- hide the voting block from comments when collapsed as the block is too narrow, it breaks the layout. It does not make sense to vote/downvote without reading a comment anyway.
- tweaked and added more precise CSS selectors (for precedence) to fix the border issues with children comments of downvoted comments