Improve color palette accessibility

[Ovgodd]

Feature Request

Hello, I'm opening a discussion about color accessibility in BlockNote. This came up during an accessibility audit of Docs (La Suite).

Audited document:
https://docs.numerique.gouv.fr/docs/0d998bef-1b69-47ce-bd18-83d4d849c734/

Is your feature request related to a problem or unsupported use case? Please describe.

The audit asks: should Docs guarantee contrast for any color a user might use?

The answer is usually no, if users could pick anything.

The real issue is not "let users pick safe colors". It's "don't offer colors in that list that break the contrast ratio".

BlockNote color palette

Right now several of those presets fail WCAG AA in common cases. The fix the audit points to is to restrict it, remove or adjust swatches that don't pass, and only show options that work for their intended use (text vs highlight background).

Contrast issues we found

We checked ratios against WCAG AA (4.5:1 for normal text).

Light mode, text color on white (#FFFFFF)

Color	Ratio	Result
yellow	2.11	Fail
gray	2.81	Fail
orange	3.28	Fail
red	4.26	Borderline (ok for large text only)
brown, green, blue, purple, pink	5.6 to 8.4	Pass

Light mode, default editor text (#3F3F3F) on highlight background

Background-only use looks fine. Everything we tested was above 8:1.

Dark mode, text color on editor background (#1F1F1F)

Color	Ratio	Result
purple	3.29	Fail
brown	3.24	Fail
pink	3.60	Fail
blue	4.09	Fail
green	4.45	Fail
red	4.22	Fail
gray, yellow, orange	above 5.5	Pass

Dark mode, default editor text (#CFCFCF) on highlight background

Color	Ratio	Result
gray	1.81	Fail
yellow	2.02	Fail
orange	2.87	Fail
red	3.61	Fail
blue	3.64	Fail
brown, purple, pink	4.3 to 5.4	Borderline

Text + background from the same family

If someone sets both (e.g. red text on red background), it gets worse:

Color	Ratio	Result
yellow	1.90	Fail
gray	2.38	Fail
orange	2.74	Fail
red	3.51	Fail

From the audit (table cells):

Ratio 3.53 - #E03E3E on #DDEDEA
Ratio 4.26 - #E03E3E on #FFFFFF

Describe the solution you'd like

Restrict the default palette so users can only pick colors that meet contrast requirements. No new free-form color picker needed.

Describe alternatives you've considered

1. Remove failing swatches from the picker. Simplest way to restrict choice.
2. Keep all names, change hex until ratios pass. Users keep the same labels, less visual churn.
3. Same 9 names but different lists for text vs background (stricter rules for text).