Only render a footer border on Dialogs with a scrolling body

[mperrotti]

Closes https://github.com/github/primer/issues/4989

Kapture.2025-04-07.at.15.12.53.mp4

Changelog

New

Changed

• Only render a border between the dialog body and the dialog footer in browsers that support CSS animation-timeline and its scroll() function

Removed

Rollout strategy

• Patch release
• Minor release
• Major release; if selected, include a written rollout or migration plan
• None; if selected, include a brief description as to why

Testing & Reviewing

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Storybook)
• Changes are SSR compatible
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge
• (GitHub staff only) Integration tests pass at github/github (Learn more about how to run integration tests)

[changeset-bot]

⚠️ No Changeset found

Latest commit: 3f6bfce

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[github-actions]

👋 Hi, this pull request contains changes to the source code that github/github depends on. If you are GitHub staff, we recommend testing these changes with github/github using the integration workflow. Thanks!

[github-actions]

size-limit report 📦

Path	Size
packages/react/dist/browser.esm.js	104.62 KB (+0.17% 🔺)
packages/react/dist/browser.umd.js	104.89 KB (+0.1% 🔺)

[hectahertz]

Loved the implementation! 🚀