test: cover @page margin properties

[Pixel998]

Prerequisites checklist

• I have read the contributing guidelines.

AI acknowledgment

• I did not use AI to generate this PR.
• (If the above is not checked) I have reviewed the AI-generated content before submitting.

What is the purpose of this pull request?

Prevent regressions where valid page-margin declarations are reported as unknown @page descriptors.

What changes did you make? (Give an overview)

Added a no-invalid-at-rules test covering margin, margin-top, margin-right, margin-bottom, and margin-left inside @page.

Related Issues

Closes #519

Is there anything you'd like reviewers to focus on?

Summary by CodeRabbit

• Tests
  • Added coverage confirming that valid @page rules with page size and margin declarations are accepted.

[DMartens]

Changes LGTM, thanks. I changed this to "blocked" as this requires csstree update (see PR).

[github-actions]

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Team

Run ID: ddaa81b6-494f-49a8-80af-f15129745a0a

📥 Commits

Reviewing files that changed from the base of the PR and between 33e7314 and e8aa24f.

📒 Files selected for processing (1)

• tests/rules/no-invalid-at-rules.test.js

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📝 Walkthrough

Walkthrough

The test suite adds a valid @page at-rule case with page size and margin declarations.

Changes

@page at-rule validation

Layer / File(s)	Summary
Valid @page descriptor test tests/rules/no-invalid-at-rules.test.js	Adds coverage for @page rules containing size and margin declarations.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Merge Risk: ⚪ Minimal · up to e8aa2

This adds regression coverage for valid @page margin descriptors without changing runtime behavior. The change is ready to merge.

Suggested reviewers: dmartens

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the test change for @page margin properties and matches the pull request content.
Linked Issues check	✅ Passed	The pull request adds a valid-case test for @page margin declarations. This directly addresses issue #519, which requires margin to be accepted without an unknown-descriptor error.
Out of Scope Changes check	✅ Passed	The only reported change is a focused test addition for @page margin descriptors. No unrelated changes are present.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 1…

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch test/page-margin-properties

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[DMartens]

Changes still LGTM, thanks.