Styles: Override user-agent margin and fix img width

[TasoOneAsia]

Proposed changes

This pull request:

• Increases the specificity of img styling to only target images rendered directly from markdown.
  • Also adds an image to the exampleSite for testing
• Removes the negative margin property assigned to the footer that could cause x-axis overflow in certain contexts. Also overrides any user-agent default margin that could cause issues as a result of the negative margin change.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md and CHANGELOG.md)

[github-actions]

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[lamATnginx]

/approve-snapshots

[github-actions]

Updating snapshots. Click here to see the status.

[github-actions]

Please download the artifacts here and commit your updated screenshots.

[lamATnginx]

LGTM to me locally. Thank you!

[github-actions]

❌ Playwright visual snapshot differences were detected.

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[TasoOneAsia]

Updated w/ signed commit