UnoCSS version

66.6.3

Describe the bug

Bug description

When using UnoCSS generate() with the scope option (e.g. scope: '.cms-scope') together with @unocss/preset-wind4, the generated CSS incorrectly prefixes Houdini @property at-rules with the scope selector, producing invalid CSS like:

.cms-scope @property --un-text-opacity { ... }

@property must be a top-level at-rule, so .cms-scope @property ... is invalid and the browser drops the entire rule. This causes preset-wind4 utilities that rely on the registered custom properties (e.g. opacity defaults like --un-text-opacity: 100%) to behave incorrectly—colors/gradients appear “washed out” because color-mix() inputs end up missing expected variables/defaults.

preset-wind4 explicitly uses @property registrations in its “properties” layer.
@property is a CSS at-rule and must be emitted as an at-rule (not combined with a selector).

Expected behavior

When scope is provided:

• Normal selectors should be scoped (e.g. .cms-scope .text-red-500 { ... })
• At-rules like @property ... should remain valid top-level rules (i.e. not be prefixed by .cms-scope)

Actual behavior

@property rules are prefixed by .cms-scope, becoming invalid and ignored by the browser.

Reproduction

Minimal script (Node)

1. Install:

npm i @unocss/core@66.6.3 @unocss/preset-wind4@66.6.3

2. Create repro.mjs:

import { createGenerator } from '@unocss/core'
import presetWind4 from '@unocss/preset-wind4'

const uno = await createGenerator({
  presets: [presetWind4()],
})

const html = `<div class="text-blue-600/50 bg-blue-100">hello</div>`

// ✅ without scope: @property is emitted correctly as a top-level at-rule
const noScope = await uno.generate(html, { minify: true, preflights: false })
console.log('--- no scope ---')
console.log(noScope.css.slice(0, 300))

// ❌ with scope: output contains invalid ".cms-scope @property ..."
const scoped = await uno.generate(html, { minify: true, preflights: false, scope: '.cms-scope' })
console.log('--- scoped ---')
console.log(scoped.css.slice(0, 300))

3. Run:

node repro.mjs

System Info

• UnoCSS: 66.6.3
• @unocss/preset-wind4: 66.6.3
• Node: (fill in, e.g. v20.x)
• Package manager: (npm/pnpm/yarn + version)
• OS: (macOS/Linux/Windows + version)
• Browser(s) affected: Any (invalid CSS rule per spec; tested in (Chrome/Firefox/Safari + version))

Validations

• Read the Contributing Guidelines.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.