Extensions: Tables & Strikethrough

CommonMark doesn't have everything. Common extensions:

GFM tables (GitHub Flavored Markdown):

| Name  | Age |
|-------|-----|
| Alice | 30  |
| Bob   | 25  |

<table>
<thead><tr><th>Name</th><th>Age</th></tr></thead>
<tbody><tr><td>Alice</td><td>30</td></tr>...</tbody>
</table>

Alignment via : in the separator row:

| Left | Center | Right |
|:-----|:------:|------:|

Strikethrough: ~~text~~ → <del>text</del>

Task lists:

- [ ] todo
- [x] done

Footnotes:

Text [^1]
[^1]: footnote content

Mermaid diagrams (in some renderers):

```mermaid
graph LR; A-->B
```

Different renderers (GitHub, GitLab, Discord, Obsidian, Notion) support different subsets. Always check what your target renders.