Add extended Markdown syntax support for superscript/subscript/highlight, footnotes, definition lists, and GFM task lists

[Copilot]

• Review current task list and footnote rendering behavior
• Update task list CSS to remove bullets for checkbox items
• Render footnote references and footnote list markers with brackets
• Adjust footnote section spacing for bottom details
• Sync desktop resource copies and validate with build
• Revert unrelated desktop resource index changes introduced by build

Original prompt

Fix Markdown feature support in repo ThisIs-Developer/Markdown-Viewer so the following features from the Markdown Feature Test Suite render correctly:

• Superscript syntax: X^2^, H^2^O
• Subscript syntax: H2O, CO2
• Highlight syntax: ==this text is highlighted==
• Task lists should render as GFM task lists (checkboxes) and not as bullet points
• Footnotes should render correctly (example in section 9 of the provided suite)
• Definition lists should render correctly (section 10)

Notes:

• The user is testing with the provided Markdown Feature Test Suite and reported these items not working.
• Ensure any necessary Markdown parser plugins or extensions are enabled and configured.
• Keep behavior aligned with GitHub-Flavored Markdown where applicable.

Provide a pull request with the fixes.

The following is the prior conversation context from the user's chat exploration (may be truncated):

User: ```

9. Footnotes

Here is a statement that needs a citation.¹

Another claim requiring evidence.²

Indent paragraphs to include them in the footnote.

You can also include `code` or **bold** in a footnote.

9. Footnotes

Here is a statement that needs a citation.¹

Another claim requiring evidence.²

Indent paragraphs to include them in the footnote.

You can also include `code` or **bold** in a footnote.

I am testing all the features of this current application using thisMarkdown Feature Test Suite
So that I can understand all the features are working when I'm testing I found syntax of features are not working and I am giving the list of features names which are not working fix this:
Superscript: X^2^, H^2^O    Subscript: H~2~O, CO~2~
Highlight: ==this text is highlighted==
The task list is also geting bulrt point fix this Task list should not yet bullet points as per the GitHub-Flavored Markdown (GFM)
9, Footnote not working
10. Definition Lists not working

Assistant: Thanks for the details. To fix those Markdown features in **ThisIs-Developer/Markdown-Viewer**, I need to look at the renderer configuration and the Markdown parsing pipeline in your repo.

Please confirm:
1) Should I make these fixes directly in **ThisIs-Developer/Markdown-Viewer**?
2) Do you want a patch (code changes) or just guidance?
3) Are you using **markdown-it**, **remark**, **marked**, or a custom parser? (If you’re not sure, I’ll find out from the repo.)

Once you confirm, I’ll inspect the repo and provide the exact code changes needed.

User: 1 assign to agent

Assistant: We’re waiting for your response to continue.

This pull request was created from Copilot chat.

Footnotes

1. This is the first footnote, short and sweet. ↩ ↩²

2. This footnote has multiple paragraphs. ↩ ↩²

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Project	Deployment	Actions	Updated (UTC)
markdown-viwer	Ready	Preview, Comment	May 15, 2026 7:16pm

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Latest commit:	3354026
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Deploying markdownviewer with    Cloudflare Pages

Latest commit:	3354026
Status:	✅  Deploy successful!
Preview URL:	https://3970b2da.markdownviewer.pages.dev
Branch Preview URL:	https://copilot-fix-markdown-feature.markdownviewer.pages.dev

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