===Requirements
[] Implement behind a feature flag (to be deployed end of April/beginning of May)
[] Add new color-blind friendly scheme to CodeMirror
[] Create a new section in Editing preferences titled 'Accessibility' and add a new preference to turn on/off color scheme
===Specifications
**Highlighting**
[] No background highlight/ background color for any type of content
[] Bolding and underlining remains unchanged
[] Four colors change (outlined in black in the image):
{F35021421}
Headings, symbols, signatures, section names, magic words: `#E4A400`
Templates: `#9C3A00`
HTML tags, references, math: `#56B4E9`
Variables: `#009E73`
**Preference**
{F35022231}
[] Add new section titled: "Accessibility" to the Editing tab of preferences
[] Add a new setting with description: "Enable colorblind-friendly scheme for syntax highlighting when editing wikitext" and sub-description (match styling of "Enable editing toolbar" preference): "If you use a gadget for syntax highlighting, this preference will not work."
===Background
- Reported on https://meta.wikimedia.org/wiki/Talk:WMDE_Technical_Wishes/Improved_Color_Scheme_of_Syntax_Highlighting
- Related request {https://phabricator.wikimedia.org/T163533}
- Implementation on the test instance: {https://phabricator.wikimedia.org/T263416}
The more accessible colors introduced in T271895 increase the contrast between the text and the background. For this many colors had to get darker, which means that the contrast between the colors actually decreased. This new scheme is introduced to emphasize contrast between colors, especially for elements that often show up next to each other in wikitext (article and templates). It has been tested for multiple types of color-blindness and is inspired by https://jfly.uni-koeln.de/color/#pallet but adapted for our context.
===Example test
Protonopia (left is current colors, right is new colors added in this ticket):
{F35021428}