develop

[srobinson]

• docs: update installation to include css-tree peer dependency

• docs: add collapse API documentation

• docs: add multiple declarations support section

[Copilot]

Pull Request Overview

This PR updates the package dependency structure by moving css-tree from dependencies to peerDependencies, and updates the documentation to reflect new functionality (collapse API) and the new installation requirement.

• Changed css-tree from a regular dependency to a peer dependency
• Updated README with documentation for the new collapse API function
• Updated installation instructions to include css-tree as a required installation
• Updated test count from 808 to 970 tests

Reviewed Changes

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

File	Description
package.json	Moved css-tree from dependencies to peerDependencies to allow consumers to control the version
README.md	Added collapse API documentation, updated installation instructions to require explicit css-tree installation, updated test count, and added bidirectional feature highlight

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

[nitpick] The example output shows { margin: '10px 20px' } but based on standard CSS margin shorthand rules, when all four sides are '10px 20px 10px 20px', it should collapse to '10px 20px' (vertical horizontal). However, this appears correct. Consider adding a comment explaining that the input has symmetrical vertical and horizontal values to make the example clearer.

Suggested change

	// → { ok: true, result: { margin: '10px 20px' }, issues: [] }
	// → { ok: true, result: { margin: '10px 20px' }, issues: [] }
	// (All four sides are symmetrical: top/bottom = 10px, left/right = 20px, so the shorthand collapses to '10px 20px')