Markdown List Renumberer

• Choose Markdown or text file (optional), or enter Markdown input. An uploaded file overrides the textarea and preserves its initial BOM and original CRLF or lone CR line endings.
• Choose List start: Keep each first number or Restart each list at 1. Only supported top-level ordered lists are targeted; their period or closing-parenthesis delimiter stays unchanged.
• Select Renumber top-level lists, then Download result to save renumbered.md. Edit input or Reset clears the result; Cancel discards unfinished work.

The lines 9. First and 1. Second become 9. First and 10. Second in keep mode. Markup, spacing, delimiters and other blocks retain their original source characters.

• Input supports 200,000 UTF-16 units, one file up to 1 MiB, 10,000 LF-separated physical lines and 10,000 targeted list items. Output is limited to 5 MiB and processing to 30 seconds.
• Only tight top-level ordered lists with single-line, non-task items are supported. Any targeted nested, loose or multiline list rejects the entire document. Blockquote-contained lists, unordered lists and fenced code are left untouched.
• List marker numbers have at most nine ASCII digits. At least one supported target is required. Source spans must be complete and contiguous; ambiguous lexer spans, including some reference-definition documents, reject rather than guess.
• The installed Markdown parser verifies the result's semantics. Post-parse traversal is limited to 20,000 tokens and 32 levels; these limits do not bound the parser's internal allocations before traversal.
• Pasted textarea line endings normalize to LF. Use a strict UTF-8 file when preserving original BOM and line-ending bytes matters. No nested renumbering, bullet conversion or delimiter normalization is provided.