Summary

source:

```mdx
<Tab label="docs/_mdx-fragment.mdx">

Check:

```mdx file="./_mdx-fragment.mdx"

```

Install:

```mdx file="./_mdx-fragment.mdx"

```


</Tab>
```

before

after

Related Issue

• close [Bug]: New Tab/Tabs component doesn't look great for content expecting gaps #3194

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

AI Summary

What changed

• Added default padding (0 1rem) and vertical margin (1rem) to .rp-tabs__content__item so that non-codeblock tab content has proper spacing.
• Used CSS :has(> .rp-codeblock:only-child) to detect when a tab panel contains only a single CodeBlock, and removes the panel padding in that case to avoid double padding.
• Added box-shadow: none to .rp-tabs .rp-codeblock to fully reset CodeBlock's standalone visual styles when nested inside Tabs (previously margin, border-radius, and border were reset but box-shadow was missed).

Why

When Tab panels had no default padding, non-codeblock content was flush against the edges. But simply adding padding caused double spacing when the tab content was a single CodeBlock (since CodeBlock has its own internal padding). The :has() CSS pseudo-class cleanly solves this without any React runtime changes.

This PR was written using Vibe Kanban