Improvement: ensure all background and foreground color combinations are suitable for color-blind people

[balupton]

Here are some current style options that are used throughout Dorothy:

I'm considering streamlining all styles into just:

Which will be more readable across the variety of themes that people use, will be consistent in no-color modes, and allows for dramatically simpler styling code.

[balupton]

Consideration for styling. The yellow and red has got to go, 1.2% of the population can't tell the difference between yellow and red.

Fascinating:

During the 17th and 18th century, several philosophers hypothesized that not all individuals perceived colors in the same way:[77]

...there is no reason to suppose a perfect resemblance in the disposition of the Optic Nerve in all Men, since there is an infinite variety in every thing in Nature, and chiefly in those that are Material, 'tis therefore very probable that all Men see not the same Colours in the same Objects.
— Nicolas Malebranche, The search after truth (1674) [78]
In the power of conceiving colors, too, there are striking differences among individuals: and, indeed, I am inclined to suspect, that, in the greater number of instances, the supposed defects of sight in this respect ought to be ascribed rather to a defect in the power of conception.
— Dugald Stewart, Elements of the philosophy of the human mind (1792) [79]

https://en.wikipedia.org/wiki/Color_blindness

[balupton]

The \nERROR:\n... to ERROR: ... suggestion has been implemented in #281. Leaving the rest of this issue for discussions on how to resolve the issue for colorblindness, including that of simplifying the styles.

Some current solutions for colorblindness:

• Use COLOR=no in your environment.* user configuration, in which Dorothy will actually adjust the content to not differentiate with colour.
• Overwrite styles.bash with your custom styles and send a PR.