Unless you’re using the 24bit color extensions, the default color choices are pretty abstract: if they are readable in one color scheme and unreadable in another, the problem is in the color scheme’s selection of colors.
In my experience most default terminal colorschemes are rather poor. You can't even make the seemingly obvious assumption that light colors have good contrast against "black" and that dark colors have good contrast against "white".
> the problem is in the color scheme’s selection of colors.
Application can also set the background colours. If I "fix" things so that it will work well on a light background then it will be broken on applications that explicitly set a dark background.
For most cases this could probably be fixed by using a more abstract color scheme: rather than "red", "blue", "grey", and such, maybe "warn_0", "emphasis_0", "dull_0", etc.
Is there a good use case for applications explicitly setting a dark background? If you're playing games in your terminal I can see it, but I'm having a hard time imagining a good use case beyond that.
Unless you’re using the 24bit color extensions, the default color choices are pretty abstract: if they are readable in one color scheme and unreadable in another, the problem is in the color scheme’s selection of colors.