Allow high-contrast input colors to be used as-is

[zenoachtig]

For step 9 of the color scale, we try to respect the user's chosen color, unless it really isn't accessible. We use a lightness check and if the color is within 20% of the target lightness, we allow it to be used even if it doesn't exactly match.

This PR changes the logic of this check slightly to no longer restrict the lower and higher contrast bounds, but only the lower bound. In practice, it means that if you have a color that is higher contrast than needed, it will now be used as-is instead of being reduced to a less-contrasting version.

This is particularly useful if you set the primary color to black on light mode, or white on dark mode. Before this would result in a grey color being used for your buttons, but now you can get exact blacks or whites since they are more contrasting anyway.

Before

After

[changeset-bot]

🦋 Changeset detected

Latest commit: 9f46181

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@gitbook/colors	Patch
gitbook	Patch

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[github-actions]

Summary of the deployments:

Version 1

Version	URL	Status
Latest commit	https://4989a192.gitbook-open.pages.dev	✅
PR	https://pr3209.gitbook-open.pages.dev	✅

Version 2

Version	URL	Status
Vercel	https://gitbook-v2-4r0491bup-gitbook.vercel.app	✅
Cloudflare	https://598a0239-gitbook-open-v2-preview.gitbook.workers.dev	✅

Test content

Site	v1	2v	2c
GitBook	https://4989a192.gitbook-open.pages.dev/docs.gitbook.com	https://gitbook-v2-4r0491bup-gitbook.vercel.app/url/docs.gitbook.com	https://598a0239-gitbook-open-v2-preview.gitbook.workers.dev/url/docs.gitbook.com
E2E	https://4989a192.gitbook-open.pages.dev/gitbook.gitbook.io/test-gitbook-open	https://gitbook-v2-4r0491bup-gitbook.vercel.app/url/gitbook.gitbook.io/test-gitbook-open	https://598a0239-gitbook-open-v2-preview.gitbook.workers.dev/url/gitbook.gitbook.io/test-gitbook-open

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Build	Status	Details	Updated (UTC)
customers-v1 (Inspect)	👍 Changes approved	18 changed	May 2, 2025, 5:32 PM
customers-v2 (Inspect)	👍 Changes approved	18 changed	May 2, 2025, 5:34 PM
default (Inspect)	👍 Changes approved	6 changed	May 2, 2025, 5:36 PM
v2-vercel (Inspect)	✅ No changes detected	-	May 2, 2025, 5:37 PM