Before publishing Markdown, compare the source with the rendered preview. Confirm headings, paragraphs, blank lines, nested lists, code fences, links, and images. A source file can look tidy while the renderer collapses a line break or treats asterisks as literal text. Check both desktop and mobile widths for long code or tables. If the destination uses a different Markdown dialect, preview there too; one renderer's output is not proof of another's.
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