Increase the touch target size of SubNav.SubMenu toggle button

[joshfarrant]

Summary

Increased the touch target size of SubNav.SubMenu toggle button to 24px × 24px.

The button was previously only 16px × 16px, and rather than add 4px to the left and right I've instead added 8px to the right (along with -8px of margin-right) so as to not cause any visual changes. You can see the touch target size change in the screenshots below.

What should reviewers focus on?

• Check that you're happy with the focus styles, and that the touch target is indeed 24px × 24px.

Supporting resources (related issues, external links, etc):

• Closes https://github.com/github/primer/issues/4676

Contributor checklist:

• All new and existing CI checks pass
• Tests prove that the feature works and covers both happy and unhappy paths
• Any drop in coverage, breaking changes or regressions have been documented above
• UI Changes contain new visual snapshots (generated by adding update snapshots label to the PR)
• All developer debugging and non-functional logging has been removed
• Related issues have been referenced in the PR description

Reviewer checklist:

• Check that pull request and proposed changes adhere to our contribution guidelines and code of conduct
• Check that tests prove the feature works and covers both happy and unhappy paths
• Check that there aren't other open Pull Requests for the same update/change

Screenshots:

Before	After

[changeset-bot]

🦋 Changeset detected

Latest commit: d4acd41

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

This PR includes changesets to release 7 packages

Name	Type
@primer/react-brand	Patch
@primer/brand-docs	Patch
@primer/brand-primitives	Patch
@primer/brand-e2e	Patch
@primer/brand-fonts	Patch
@primer/brand-config	Patch
@primer/brand-storybook	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

🟢 No design token changes found

[Copilot]

Pull Request Overview

Increases the touch target size of the SubNav.SubMenu toggle button from 16×16 to 24×24 without altering its visual position by adding height, inline padding, and compensating negative margin.

• Adjusted .SubNav__sub-menu-toggle CSS to enforce a 24px height and expand clickable area.
• Provided a changeset entry to document the patch release.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
packages/react/src/SubNav/SubNav.module.css	Added height, padding-inline-end, and margin-inline-end to expand the toggle’s touch target
.changeset/tiny-bears-lick.md	Introduced a changeset recording the UI adjustment

Comments suppressed due to low confidence (1)

packages/react/src/SubNav/SubNav.module.css:633

• It looks like there isn’t an updated visual snapshot or test verifying the new 24×24 touch target; consider adding or updating a snapshot to catch regressions for this change.

height: var(--base-size-24);

[github-actions]

🟢 No visual differences found

Our visual comparison tests did not find any differences in the UI.

[danielguillan]

LGTM!