# ForTheme

> Content kept for one theme only.

Keeps its content for the sites whose theme matches. The choice is made at
build time: the other variant does not even reach the HTML.

```mdx
<ForTheme framework="tailwind">

With Tailwind, a utility: `className="max-w-sm"`.

</ForTheme>
<ForTheme framework="custom">

With the custom theme, a class of the `theme/` folder: `className="narrow"`.

</ForTheme>
```

It is how the pages of this documentation show each example in the terms of
your theme. Changing `theme.framework` in the configuration changes what they
show, without editing them.

## On this site

<ForTheme framework="tailwind">

This site is built with the **Tailwind** theme.

</ForTheme>
<ForTheme framework="custom">

This site is built with the **custom** theme.

</ForTheme>

## What it refuses

A `framework` other than `tailwind` or `custom` stops the build, with the
accepted values: a typo would otherwise hide the content under every theme,
without a word.

Which theme a project runs is one field of its configuration, and the whole
of what it changes is in [Themes](/versions/latest/guide/themes/).