* Opt-in for light and dark color schemes
* Convert scss variables in _light.scss to css variables
* Add _dark.scss for dark color scheme
* Remove unused, theme-related variables
- Set min-width and min-height to width and height so buttons never shrink
- Remove defunct .zotero-clicky-* styles from 2x block in zotero.css
- Include zotero-platform/content/zotero.css in searchDialog.xhtml
- It seems only the defunct 2x styles from zotero.css were being applied, so
the buttons would have been unstyled on a non-hiDPI display
- Render cell text in its native direction
- Fix context menu positioning
- Fix item box (localizations needed)
- Fix column resizing
- Fix bidi text in collection tree
- Always right-align in RTL, always left-align in LTR.
I'm going off advice from this excellent guide for RTL website design
by Ahmad Shadeed: https://rtlstyling.com/posts/rtl-styling#tables
- Join creators in the tree ("Smith and Jones") using a format string to
support languages like Arabic and Hebrew where there shouldn't be a
space after the "and".
- Fix tabs
- Fix toolbar on Mac, flip icons on other platforms
