A margin exists between the tabs and the actual code when code groups are used in custom blocks

[sapphi-red]

Describe the bug

::::info

::: code-group

```js [foo.js]
console.log('foo')
```

:::

::::

Reproduction

https://stackblitz.com/edit/vite-jlmcekec?file=docs%2Fexample.md

Expected behavior

The margin to not exist.

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 20.19.1 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.8.2 - /usr/local/bin/npm
    pnpm: 8.15.6 - /usr/local/bin/pnpm
  npmPackages:
    vitepress: ^2.0.0-alpha => 2.0.0-alpha.15

Additional context

It is caused by this line. But I'm not sure the purpose of this line.

vitepress/src/client/theme-default/styles/components/vp-doc.css

Line 229 in f8d8c0d

margin: 8px 0 !important;

Validations

• Check if you're on the latest VitePress version.
• Follow our Code of Conduct
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.

[brc-dd]

But I'm not sure of the purpose of this line.

Original intent was to separate the code blocks #4921. But that margin is not needed for code blocks inside code groups. It's specificity issue. vp-code-groups.css has overrides for those, but their specificity is less.