Documentation Accessibility - Color Scheme

[JoeCalvert]

What's the problem?

The color scheme of the docs site gives titles a very low contrast ratio. Being colourblind, this makes them hard to read.
Updating the color scheme to follow WCAG 2 guidelines would provide a much better experience for general users and improve readability for users that have issues with their vision

WAVE report
WhoCanUse Contrast Assessment

Fixes

• Decide on a color palette that can be used to update the design of the documentation site
• Assess the color palette for accessibility against WCAG 2 guidelines
• Update the site theme with the new colours

Suggestions

Updating the theme provides an opportunity to update the design tokens found in voron-dark.scss to be self-documenting. For example, having tokens such as background-dark and on-background-dark instead of grey-dk-400 and voron-red-60. This could help to reduce design issues in future changes

[nemgrea]

i believe this should be resolved by pull request #293