Markdown was created by John Gruber in 2004 as a simple, readable text-to-HTML conversion syntax. Its design philosophy is that the source text should be readable as-is, without rendering -- a Markdown document with # Heading and **bold** text is understandable even in a plain text editor. This contrasts with HTML, where

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Le Markdown GitHub-Flavored (GFM) étend la spécification Markdown originale avec des fonctionnalités demandées par les développeurs : blocs de code clôturés (`language), tableaux (| Colonne | Colonne |), listes de tâches (- [x] fait), barré (~~texte~~) et lien automatique des URL. GFM est la variante Markdown la plus largement utilisée, prise en charge par GitHub, GitLab, Bitbucket, Discord, Reddit et de nombreuses autres plateformes. Notre éditeur rend le GFM à l'aide de la bibliothèque marked.js, qui est un analyseur Markdown rapide et conforme à la spécification.

Writing in Markdown has several advantages over WYSIWYG editors (like Microsoft Word or Google Docs): the files are plain text (future-proof, version-control friendly, searchable), the formatting is semantic (you describe what things are, not how they look), and the source is portable (works in any text editor). The separation of content and presentation means the same Markdown file can be rendered as HTML, PDF, EPUB, or slides with different styling.

Use ATX-style headings (# for H1, ## for H2) with a space after the hash. Setext-style headings (underlining with === or ---) is deprecated in GFM. Leave a blank line before and after headings, lists, and code blocks -- many parsers require this for correct rendering. For emphasis, use **bold** and *italic* (asterisks) consistently. Avoid using _ for emphasis as it can conflict with variable names in technical documentation.

For code blocks, always specify the language for syntax highlighting: use triple backticks followed by the language name (javascript, python, bash). For inline code, use single backticks around the word. For links, use [text](url) format. For images, use . For tables, use the pipe syntax with a separator row: | Header | Header | / | --- | --- | / | Cell | Cell |. Tables must have a header row and a separator row -- cells in the body can be left empty but the structure must be maintained.