I'm trying to make a rough and ready light theme, as I find dark themes very unpleasant to use.
So for starters I've just taken the default theme and inverted all the colours (e.g. #3E3E3E -> #C1C1C1).
This produces a basically usable colour scheme but the icons (e.g. on the tab bar, and all the on/off switches) have very little contrast. It's not clear to me where these are set, can anybody explain where to set them,