This should simplify things regarding different styles on different states of the button, LTR/RTL icons etc.
Note: I am thinking of making those arrows framed OOjs UI ButtonWidgets with next/previous icons. This would affect the existing UI at least in a following way:
- icons will be slightly smaller than existing ones. See 'next' and 'previous' icons here: https://doc.wikimedia.org/oojs-ui/master/demos/#icons-mediawiki-ltr and https://doc.wikimedia.org/oojs-ui/master/demos/#icons-mediawiki-rtl. This icons are RTL-compliant (ie. they flip depending on what direction user is using). Possible alternative, ie. icons 'caretLast' and 'caretNext' does not seem RTL-friendly looking at those demo pages, so I would go with 'next' and 'previous'
- border around buttons will be thinner (one pixel instead of two)
- (most significant difference) disabled arrows will look like disabled button, as e.g. disabled ones here: https://doc.wikimedia.org/oojs-ui/master/demos/#widgets-mediawiki-ltr (slightly darker grey than now, white icon instead of black one)
Some screen caps how arrow buttons (would) look like after the change.
And some close ups to button in hover and active (mouse button pressed and not released) state to have all combinations visible: