diff --git a/packages/tailwindcss-language-server/src/oxide.ts b/packages/tailwindcss-language-server/src/oxide.ts
index 5dad7553..4dd529df 100644
--- a/packages/tailwindcss-language-server/src/oxide.ts
+++ b/packages/tailwindcss-language-server/src/oxide.ts
@@ -36,8 +36,8 @@ declare namespace OxideV2 {
   }
 }
 
-// This covers the Oxide API from v4.0.0-alpha.20+
-declare namespace OxideV3 {
+// This covers the Oxide API from v4.0.0-alpha.30+
+declare namespace OxideV3And4 {
   interface GlobEntry {
     base: string
     pattern: string
@@ -58,10 +58,37 @@ declare namespace OxideV3 {
   }
 }
 
+// This covers the Oxide API from v4.1.0+
+declare namespace OxideV5 {
+  interface GlobEntry {
+    base: string
+    pattern: string
+  }
+
+  interface SourceEntry {
+    base: string
+    pattern: string
+    negated: boolean
+  }
+
+  interface ScannerOptions {
+    sources: Array<SourceEntry>
+  }
+
+  interface ScannerConstructor {
+    new (options: ScannerOptions): Scanner
+  }
+
+  interface Scanner {
+    get files(): Array<string>
+    get globs(): Array<GlobEntry>
+  }
+}
+
 interface Oxide {
   scanDir?(options: OxideV1.ScanOptions): OxideV1.ScanResult
   scanDir?(options: OxideV2.ScanOptions): OxideV2.ScanResult
-  Scanner?: OxideV3.ScannerConstructor
+  Scanner?: OxideV3And4.ScannerConstructor | OxideV5.ScannerConstructor
 }
 
 async function loadOxideAtPath(id: string): Promise<Oxide | null> {
@@ -78,11 +105,17 @@ interface GlobEntry {
   pattern: string
 }
 
+interface SourceEntry {
+  base: string
+  pattern: string
+  negated: boolean
+}
+
 interface ScanOptions {
   oxidePath: string
   oxideVersion: string
   basePath: string
-  sources: Array<GlobEntry>
+  sources: Array<SourceEntry>
 }
 
 interface ScanResult {
@@ -118,38 +151,58 @@ export async function scan(options: ScanOptions): Promise<ScanResult | null> {
   }
 
   // V2
-  if (lte(options.oxideVersion, '4.0.0-alpha.19')) {
+  else if (lte(options.oxideVersion, '4.0.0-alpha.19')) {
     let result = oxide.scanDir({
       base: options.basePath,
-      sources: options.sources,
+      sources: options.sources.map((g) => ({ base: g.base, pattern: g.pattern })),
     })
 
     return {
       files: result.files,
-      globs: result.globs,
+      globs: result.globs.map((g) => ({ base: g.base, pattern: g.pattern })),
     }
   }
 
   // V3
-  if (lte(options.oxideVersion, '4.0.0-alpha.30')) {
-    let scanner = new oxide.Scanner({
+  else if (lte(options.oxideVersion, '4.0.0-alpha.30')) {
+    let scanner = new (oxide.Scanner as OxideV3And4.ScannerConstructor)({
       detectSources: { base: options.basePath },
-      sources: options.sources,
+      sources: options.sources.map((g) => ({ base: g.base, pattern: g.pattern })),
     })
 
     return {
       files: scanner.files,
-      globs: scanner.globs,
+      globs: scanner.globs.map((g) => ({ base: g.base, pattern: g.pattern })),
     }
   }
 
   // V4
-  let scanner = new oxide.Scanner({
-    sources: [{ base: options.basePath, pattern: '**/*' }, ...options.sources],
-  })
+  else if (lte(options.oxideVersion, '4.0.9999')) {
+    let scanner = new (oxide.Scanner as OxideV3And4.ScannerConstructor)({
+      sources: [
+        { base: options.basePath, pattern: '**/*' },
+        ...options.sources.map((g) => ({ base: g.base, pattern: g.pattern })),
+      ],
+    })
 
-  return {
-    files: scanner.files,
-    globs: scanner.globs,
+    return {
+      files: scanner.files,
+      globs: scanner.globs.map((g) => ({ base: g.base, pattern: g.pattern })),
+    }
+  }
+
+  // V5
+  else {
+    let scanner = new (oxide.Scanner as OxideV5.ScannerConstructor)({
+      sources: [
+        { base: options.basePath, pattern: '**/*', negated: false },
+        ...options.sources.map((g) => ({ base: g.base, pattern: g.pattern, negated: g.negated })),
+      ],
+    })
+
+    return {
+      files: scanner.files,
+      globs: scanner.globs.map((g) => ({ base: g.base, pattern: g.pattern })),
+    }
   }
 }
diff --git a/packages/tailwindcss-language-server/src/project-locator.test.ts b/packages/tailwindcss-language-server/src/project-locator.test.ts
index 52af6446..ae3598e5 100644
--- a/packages/tailwindcss-language-server/src/project-locator.test.ts
+++ b/packages/tailwindcss-language-server/src/project-locator.test.ts
@@ -4,7 +4,7 @@ import { ProjectLocator } from './project-locator'
 import { URL, fileURLToPath } from 'url'
 import { Settings } from '@tailwindcss/language-service/src/util/state'
 import { createResolver } from './resolver'
-import { css, defineTest, js, json, scss, Storage, TestUtils } from './testing'
+import { css, defineTest, html, js, json, scss, Storage, symlinkTo, TestUtils } from './testing'
 import { normalizePath } from './utils'
 
 let settings: Settings = {
@@ -141,58 +141,129 @@ testFixture('v4/workspaces', [
   },
 ])
 
-testFixture('v4/auto-content', [
-  //
-  {
-    config: 'src/app.css',
-    content: [
-      '{URL}/*',
-      '{URL}/package.json',
-      '{URL}/src/index.html',
-      '{URL}/src/components/example.html',
-      '{URL}/src/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
-    ],
+testLocator({
+  name: 'automatic content detection with Oxide',
+  fs: {
+    'package.json': json`
+      {
+        "dependencies": {
+          "tailwindcss": "^4.0.15",
+          "@tailwindcss/oxide": "^4.0.15"
+        }
+      }
+    `,
+    'src/index.html': html`<div class="flex">Test</div>`,
+    'src/app.css': css`
+      @import 'tailwindcss';
+    `,
+    'src/components/example.html': html`<div class="underline">Test</div>`,
   },
-])
+  expected: [
+    {
+      config: '/src/app.css',
+      content: [
+        '/*',
+        '/package.json',
+        '/src/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
+        '/src/components/example.html',
+        '/src/index.html',
+      ],
+    },
+  ],
+})
 
-testFixture('v4/auto-content-split', [
-  {
-    config: 'src/app.css',
-    content: [
-      '{URL}/*',
-      '{URL}/package.json',
-      '{URL}/src/index.html',
-      '{URL}/src/components/example.html',
-      '{URL}/src/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
-    ],
+testLocator({
+  name: 'automatic content detection with Oxide using split config',
+  fs: {
+    'package.json': json`
+      {
+        "dependencies": {
+          "tailwindcss": "^4.0.15",
+          "@tailwindcss/oxide": "^4.0.15"
+        }
+      }
+    `,
+    'src/index.html': html`<div class="flex">Test</div>`,
+    'src/app.css': css`
+      @import 'tailwindcss/preflight' layer(base);
+      @import 'tailwindcss/theme' layer(theme);
+      @import 'tailwindcss/utilities' layer(utilities);
+    `,
+    'src/components/example.html': html`<div class="underline">Test</div>`,
   },
-])
+  expected: [
+    {
+      config: '/src/app.css',
+      content: [
+        '/*',
+        '/package.json',
+        '/src/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
+        '/src/components/example.html',
+        '/src/index.html',
+      ],
+    },
+  ],
+})
 
-testFixture('v4/custom-source', [
-  //
-  {
-    config: 'admin/app.css',
-    content: [
-      '{URL}/*',
-      '{URL}/admin/foo.bin',
-      '{URL}/admin/{**/*.bin,**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}}',
-      '{URL}/package.json',
-      '{URL}/shared.html',
-      '{URL}/web/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
-    ],
-  },
-  {
-    config: 'web/app.css',
-    content: [
-      '{URL}/*',
-      '{URL}/admin/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
-      '{URL}/package.json',
-      '{URL}/shared.html',
-      '{URL}/web/bar.bin',
-      '{URL}/web/{**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue},*.bin}',
-    ],
+testLocator({
+  name: 'automatic content detection with custom sources',
+  fs: {
+    'package.json': json`
+      {
+        "dependencies": {
+          "tailwindcss": "^4.0.15",
+          "@tailwindcss/oxide": "^4.0.15"
+        }
+      }
+    `,
+    'admin/app.css': css`
+      @import './tw.css';
+      @import './ui.css';
+    `,
+    'admin/tw.css': css`
+      @import 'tailwindcss';
+      @source './**/*.bin';
+    `,
+    'admin/ui.css': css`
+      @theme {
+        --color-potato: #907a70;
+      }
+    `,
+    'admin/foo.bin': html`<p class="underline">Admin</p>`,
+
+    'web/app.css': css`
+      @import 'tailwindcss';
+      @source './*.bin';
+    `,
+    'web/bar.bin': html`<p class="underline">Web</p>`,
+
+    'shared.html': html`<p>I belong to no one!</p>`,
   },
-])
+  expected: [
+    {
+      config: '/admin/app.css',
+      content: [
+        '/*',
+        '/admin/foo.bin',
+        '/admin/{**/*.bin,**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}}',
+        '/package.json',
+        '/shared.html',
+        '/web/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
+      ],
+    },
+    {
+      config: '/web/app.css',
+      content: [
+        '/*',
+        '/admin/**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue}',
+        '/package.json',
+        '/shared.html',
+        '/web/bar.bin',
+        '/web/{**/*.{aspx,astro,cjs,cts,eex,erb,gjs,gts,haml,handlebars,hbs,heex,html,jade,js,jsx,liquid,md,mdx,mjs,mts,mustache,njk,nunjucks,php,pug,py,razor,rb,rhtml,rs,slim,svelte,tpl,ts,tsx,twig,vue},*.bin}',
+      ],
+    },
+  ],
+})
 
 testFixture('v4/missing-files', [
   //
diff --git a/packages/tailwindcss-language-server/src/project-locator.ts b/packages/tailwindcss-language-server/src/project-locator.ts
index 460b1423..c75ae1de 100644
--- a/packages/tailwindcss-language-server/src/project-locator.ts
+++ b/packages/tailwindcss-language-server/src/project-locator.ts
@@ -627,12 +627,9 @@ async function* detectContentFiles(
   resolver: Resolver,
 ): AsyncIterable<string> {
   try {
-    let oxidePath = await resolver.resolveJsId('@tailwindcss/oxide', path.dirname(base))
+    let oxidePath = await resolver.resolveJsId('@tailwindcss/oxide', base)
     oxidePath = pathToFileURL(oxidePath).href
-    let oxidePackageJsonPath = await resolver.resolveJsId(
-      '@tailwindcss/oxide/package.json',
-      path.dirname(base),
-    )
+    let oxidePackageJsonPath = await resolver.resolveJsId('@tailwindcss/oxide/package.json', base)
     let oxidePackageJson = JSON.parse(await fs.readFile(oxidePackageJsonPath, 'utf8'))
 
     let result = await oxide.scan({
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/package-lock.json b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/package-lock.json
deleted file mode 100644
index b829f613..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/package-lock.json
+++ /dev/null
@@ -1,217 +0,0 @@
-{
-  "name": "auto-content-split",
-  "lockfileVersion": 3,
-  "requires": true,
-  "packages": {
-    "": {
-      "dependencies": {
-        "@tailwindcss/oxide": "^4.0.15",
-        "tailwindcss": "^4.0.15"
-      }
-    },
-    "node_modules/@tailwindcss/oxide": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide/-/oxide-4.0.15.tgz",
-      "integrity": "sha512-e0uHrKfPu7JJGMfjwVNyt5M0u+OP8kUmhACwIRlM+JNBuReDVQ63yAD1NWe5DwJtdaHjugNBil76j+ks3zlk6g==",
-      "license": "MIT",
-      "engines": {
-        "node": ">= 10"
-      },
-      "optionalDependencies": {
-        "@tailwindcss/oxide-android-arm64": "4.0.15",
-        "@tailwindcss/oxide-darwin-arm64": "4.0.15",
-        "@tailwindcss/oxide-darwin-x64": "4.0.15",
-        "@tailwindcss/oxide-freebsd-x64": "4.0.15",
-        "@tailwindcss/oxide-linux-arm-gnueabihf": "4.0.15",
-        "@tailwindcss/oxide-linux-arm64-gnu": "4.0.15",
-        "@tailwindcss/oxide-linux-arm64-musl": "4.0.15",
-        "@tailwindcss/oxide-linux-x64-gnu": "4.0.15",
-        "@tailwindcss/oxide-linux-x64-musl": "4.0.15",
-        "@tailwindcss/oxide-win32-arm64-msvc": "4.0.15",
-        "@tailwindcss/oxide-win32-x64-msvc": "4.0.15"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-android-arm64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-android-arm64/-/oxide-android-arm64-4.0.15.tgz",
-      "integrity": "sha512-EBuyfSKkom7N+CB3A+7c0m4+qzKuiN0WCvzPvj5ZoRu4NlQadg/mthc1tl5k9b5ffRGsbDvP4k21azU4VwVk3Q==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "android"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-darwin-arm64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-darwin-arm64/-/oxide-darwin-arm64-4.0.15.tgz",
-      "integrity": "sha512-ObVAnEpLepMhV9VoO0JSit66jiN5C4YCqW3TflsE9boo2Z7FIjV80RFbgeL2opBhtxbaNEDa6D0/hq/EP03kgQ==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "darwin"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-darwin-x64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-darwin-x64/-/oxide-darwin-x64-4.0.15.tgz",
-      "integrity": "sha512-IElwoFhUinOr9MyKmGTPNi1Rwdh68JReFgYWibPWTGuevkHkLWKEflZc2jtI5lWZ5U9JjUnUfnY43I4fEXrc4g==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "darwin"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-freebsd-x64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-freebsd-x64/-/oxide-freebsd-x64-4.0.15.tgz",
-      "integrity": "sha512-6BLLqyx7SIYRBOnTZ8wgfXANLJV5TQd3PevRJZp0vn42eO58A2LykRKdvL1qyPfdpmEVtF+uVOEZ4QTMqDRAWA==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "freebsd"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-arm-gnueabihf": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-arm-gnueabihf/-/oxide-linux-arm-gnueabihf-4.0.15.tgz",
-      "integrity": "sha512-Zy63EVqO9241Pfg6G0IlRIWyY5vNcWrL5dd2WAKVJZRQVeolXEf1KfjkyeAAlErDj72cnyXObEZjMoPEKHpdNw==",
-      "cpu": [
-        "arm"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-arm64-gnu": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-arm64-gnu/-/oxide-linux-arm64-gnu-4.0.15.tgz",
-      "integrity": "sha512-2NemGQeaTbtIp1Z2wyerbVEJZTkAWhMDOhhR5z/zJ75yMNf8yLnE+sAlyf6yGDNr+1RqvWrRhhCFt7i0CIxe4Q==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-arm64-musl": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-arm64-musl/-/oxide-linux-arm64-musl-4.0.15.tgz",
-      "integrity": "sha512-342GVnhH/6PkVgKtEzvNVuQ4D+Q7B7qplvuH20Cfz9qEtydG6IQczTZ5IT4JPlh931MG1NUCVxg+CIorr1WJyw==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-x64-gnu": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-x64-gnu/-/oxide-linux-x64-gnu-4.0.15.tgz",
-      "integrity": "sha512-g76GxlKH124RuGqacCEFc2nbzRl7bBrlC8qDQMiUABkiifDRHOIUjgKbLNG4RuR9hQAD/MKsqZ7A8L08zsoBrw==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-x64-musl": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-x64-musl/-/oxide-linux-x64-musl-4.0.15.tgz",
-      "integrity": "sha512-Gg/Y1XrKEvKpq6WeNt2h8rMIKOBj/W3mNa5NMvkQgMC7iO0+UNLrYmt6zgZufht66HozNpn+tJMbbkZ5a3LczA==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-win32-arm64-msvc": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-win32-arm64-msvc/-/oxide-win32-arm64-msvc-4.0.15.tgz",
-      "integrity": "sha512-7QtSSJwYZ7ZK1phVgcNZpuf7c7gaCj8Wb0xjliligT5qCGCp79OV2n3SJummVZdw4fbTNKUOYMO7m1GinppZyA==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "win32"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-win32-x64-msvc": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-win32-x64-msvc/-/oxide-win32-x64-msvc-4.0.15.tgz",
-      "integrity": "sha512-JQ5H+5MLhOjpgNp6KomouE0ZuKmk3hO5h7/ClMNAQ8gZI2zkli3IH8ZqLbd2DVfXDbdxN2xvooIEeIlkIoSCqw==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "win32"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/tailwindcss": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.0.15.tgz",
-      "integrity": "sha512-6ZMg+hHdMJpjpeCCFasX7K+U615U9D+7k5/cDK/iRwl6GptF24+I/AbKgOnXhVKePzrEyIXutLv36n4cRsq3Sg==",
-      "license": "MIT"
-    }
-  }
-}
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/package.json b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/package.json
deleted file mode 100644
index 908f1d2f..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/package.json
+++ /dev/null
@@ -1,6 +0,0 @@
-{
-  "dependencies": {
-    "tailwindcss": "^4.0.15",
-    "@tailwindcss/oxide": "^4.0.15"
-  }
-}
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/app.css b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/app.css
deleted file mode 100644
index 7b4dcc31..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/app.css
+++ /dev/null
@@ -1,3 +0,0 @@
-@import "tailwindcss/preflight" layer(base);
-@import "tailwindcss/theme" layer(theme);
-@import "tailwindcss/utilities" layer(utilities);
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/components/example.html b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/components/example.html
deleted file mode 100644
index 788b45c9..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/components/example.html
+++ /dev/null
@@ -1 +0,0 @@
-<div class="underline">Test</div>
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/index.html b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/index.html
deleted file mode 100644
index a108a449..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content-split/src/index.html
+++ /dev/null
@@ -1 +0,0 @@
-<div class="flex">Test</div>
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/package-lock.json b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/package-lock.json
deleted file mode 100644
index 6b32300e..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/package-lock.json
+++ /dev/null
@@ -1,217 +0,0 @@
-{
-  "name": "auto-content",
-  "lockfileVersion": 3,
-  "requires": true,
-  "packages": {
-    "": {
-      "dependencies": {
-        "@tailwindcss/oxide": "^4.0.15",
-        "tailwindcss": "^4.0.15"
-      }
-    },
-    "node_modules/@tailwindcss/oxide": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide/-/oxide-4.0.15.tgz",
-      "integrity": "sha512-e0uHrKfPu7JJGMfjwVNyt5M0u+OP8kUmhACwIRlM+JNBuReDVQ63yAD1NWe5DwJtdaHjugNBil76j+ks3zlk6g==",
-      "license": "MIT",
-      "engines": {
-        "node": ">= 10"
-      },
-      "optionalDependencies": {
-        "@tailwindcss/oxide-android-arm64": "4.0.15",
-        "@tailwindcss/oxide-darwin-arm64": "4.0.15",
-        "@tailwindcss/oxide-darwin-x64": "4.0.15",
-        "@tailwindcss/oxide-freebsd-x64": "4.0.15",
-        "@tailwindcss/oxide-linux-arm-gnueabihf": "4.0.15",
-        "@tailwindcss/oxide-linux-arm64-gnu": "4.0.15",
-        "@tailwindcss/oxide-linux-arm64-musl": "4.0.15",
-        "@tailwindcss/oxide-linux-x64-gnu": "4.0.15",
-        "@tailwindcss/oxide-linux-x64-musl": "4.0.15",
-        "@tailwindcss/oxide-win32-arm64-msvc": "4.0.15",
-        "@tailwindcss/oxide-win32-x64-msvc": "4.0.15"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-android-arm64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-android-arm64/-/oxide-android-arm64-4.0.15.tgz",
-      "integrity": "sha512-EBuyfSKkom7N+CB3A+7c0m4+qzKuiN0WCvzPvj5ZoRu4NlQadg/mthc1tl5k9b5ffRGsbDvP4k21azU4VwVk3Q==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "android"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-darwin-arm64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-darwin-arm64/-/oxide-darwin-arm64-4.0.15.tgz",
-      "integrity": "sha512-ObVAnEpLepMhV9VoO0JSit66jiN5C4YCqW3TflsE9boo2Z7FIjV80RFbgeL2opBhtxbaNEDa6D0/hq/EP03kgQ==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "darwin"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-darwin-x64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-darwin-x64/-/oxide-darwin-x64-4.0.15.tgz",
-      "integrity": "sha512-IElwoFhUinOr9MyKmGTPNi1Rwdh68JReFgYWibPWTGuevkHkLWKEflZc2jtI5lWZ5U9JjUnUfnY43I4fEXrc4g==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "darwin"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-freebsd-x64": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-freebsd-x64/-/oxide-freebsd-x64-4.0.15.tgz",
-      "integrity": "sha512-6BLLqyx7SIYRBOnTZ8wgfXANLJV5TQd3PevRJZp0vn42eO58A2LykRKdvL1qyPfdpmEVtF+uVOEZ4QTMqDRAWA==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "freebsd"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-arm-gnueabihf": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-arm-gnueabihf/-/oxide-linux-arm-gnueabihf-4.0.15.tgz",
-      "integrity": "sha512-Zy63EVqO9241Pfg6G0IlRIWyY5vNcWrL5dd2WAKVJZRQVeolXEf1KfjkyeAAlErDj72cnyXObEZjMoPEKHpdNw==",
-      "cpu": [
-        "arm"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-arm64-gnu": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-arm64-gnu/-/oxide-linux-arm64-gnu-4.0.15.tgz",
-      "integrity": "sha512-2NemGQeaTbtIp1Z2wyerbVEJZTkAWhMDOhhR5z/zJ75yMNf8yLnE+sAlyf6yGDNr+1RqvWrRhhCFt7i0CIxe4Q==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-arm64-musl": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-arm64-musl/-/oxide-linux-arm64-musl-4.0.15.tgz",
-      "integrity": "sha512-342GVnhH/6PkVgKtEzvNVuQ4D+Q7B7qplvuH20Cfz9qEtydG6IQczTZ5IT4JPlh931MG1NUCVxg+CIorr1WJyw==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-x64-gnu": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-x64-gnu/-/oxide-linux-x64-gnu-4.0.15.tgz",
-      "integrity": "sha512-g76GxlKH124RuGqacCEFc2nbzRl7bBrlC8qDQMiUABkiifDRHOIUjgKbLNG4RuR9hQAD/MKsqZ7A8L08zsoBrw==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-linux-x64-musl": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-linux-x64-musl/-/oxide-linux-x64-musl-4.0.15.tgz",
-      "integrity": "sha512-Gg/Y1XrKEvKpq6WeNt2h8rMIKOBj/W3mNa5NMvkQgMC7iO0+UNLrYmt6zgZufht66HozNpn+tJMbbkZ5a3LczA==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "linux"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-win32-arm64-msvc": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-win32-arm64-msvc/-/oxide-win32-arm64-msvc-4.0.15.tgz",
-      "integrity": "sha512-7QtSSJwYZ7ZK1phVgcNZpuf7c7gaCj8Wb0xjliligT5qCGCp79OV2n3SJummVZdw4fbTNKUOYMO7m1GinppZyA==",
-      "cpu": [
-        "arm64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "win32"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/@tailwindcss/oxide-win32-x64-msvc": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/@tailwindcss/oxide-win32-x64-msvc/-/oxide-win32-x64-msvc-4.0.15.tgz",
-      "integrity": "sha512-JQ5H+5MLhOjpgNp6KomouE0ZuKmk3hO5h7/ClMNAQ8gZI2zkli3IH8ZqLbd2DVfXDbdxN2xvooIEeIlkIoSCqw==",
-      "cpu": [
-        "x64"
-      ],
-      "license": "MIT",
-      "optional": true,
-      "os": [
-        "win32"
-      ],
-      "engines": {
-        "node": ">= 10"
-      }
-    },
-    "node_modules/tailwindcss": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.0.15.tgz",
-      "integrity": "sha512-6ZMg+hHdMJpjpeCCFasX7K+U615U9D+7k5/cDK/iRwl6GptF24+I/AbKgOnXhVKePzrEyIXutLv36n4cRsq3Sg==",
-      "license": "MIT"
-    }
-  }
-}
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/package.json b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/package.json
deleted file mode 100644
index 908f1d2f..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/package.json
+++ /dev/null
@@ -1,6 +0,0 @@
-{
-  "dependencies": {
-    "tailwindcss": "^4.0.15",
-    "@tailwindcss/oxide": "^4.0.15"
-  }
-}
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/app.css b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/app.css
deleted file mode 100644
index d4b50785..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/app.css
+++ /dev/null
@@ -1 +0,0 @@
-@import 'tailwindcss';
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/components/example.html b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/components/example.html
deleted file mode 100644
index 788b45c9..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/components/example.html
+++ /dev/null
@@ -1 +0,0 @@
-<div class="underline">Test</div>
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/index.html b/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/index.html
deleted file mode 100644
index a108a449..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/auto-content/src/index.html
+++ /dev/null
@@ -1 +0,0 @@
-<div class="flex">Test</div>
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/app.css b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/app.css
deleted file mode 100644
index 41dcb5f8..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/app.css
+++ /dev/null
@@ -1,2 +0,0 @@
-@import './tw.css';
-@import './ui.css';
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/foo.bin b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/foo.bin
deleted file mode 100644
index ec56c434..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/foo.bin
+++ /dev/null
@@ -1 +0,0 @@
-<p class="underline">Admin</p>
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/tw.css b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/tw.css
deleted file mode 100644
index 9c0a7919..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/tw.css
+++ /dev/null
@@ -1,2 +0,0 @@
-@import 'tailwindcss';
-@source './**/*.bin';
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/ui.css b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/ui.css
deleted file mode 100644
index 24ea64d2..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/admin/ui.css
+++ /dev/null
@@ -1,3 +0,0 @@
-@theme {
-  --color-potato: #907a70;
-}
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/package-lock.json b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/package-lock.json
deleted file mode 100644
index ce004f1d..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/package-lock.json
+++ /dev/null
@@ -1,18 +0,0 @@
-{
-  "name": "custom-source",
-  "lockfileVersion": 3,
-  "requires": true,
-  "packages": {
-    "": {
-      "dependencies": {
-        "tailwindcss": "^4.0.15"
-      }
-    },
-    "node_modules/tailwindcss": {
-      "version": "4.0.15",
-      "resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.0.15.tgz",
-      "integrity": "sha512-6ZMg+hHdMJpjpeCCFasX7K+U615U9D+7k5/cDK/iRwl6GptF24+I/AbKgOnXhVKePzrEyIXutLv36n4cRsq3Sg==",
-      "license": "MIT"
-    }
-  }
-}
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/package.json b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/package.json
deleted file mode 100644
index b6cb53b1..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/package.json
+++ /dev/null
@@ -1,5 +0,0 @@
-{
-  "dependencies": {
-    "tailwindcss": "^4.0.15"
-  }
-}
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/shared.html b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/shared.html
deleted file mode 100644
index 49b293bf..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/shared.html
+++ /dev/null
@@ -1 +0,0 @@
-<p>I belong to no one!</p>
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/web/app.css b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/web/app.css
deleted file mode 100644
index 9357eb02..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/web/app.css
+++ /dev/null
@@ -1,2 +0,0 @@
-@import 'tailwindcss';
-@source './*.bin';
diff --git a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/web/bar.bin b/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/web/bar.bin
deleted file mode 100644
index 56ee61a2..00000000
--- a/packages/tailwindcss-language-server/tests/fixtures/v4/custom-source/web/bar.bin
+++ /dev/null
@@ -1 +0,0 @@
-<p class="underline">Web</p>