diff --git a/packages/internal-postcss-fix-relative-paths/src/fixtures/example-project/src/index.css b/packages/internal-postcss-fix-relative-paths/src/fixtures/example-project/src/index.css
index 112e82e59673..f71b89bbb05b 100644
--- a/packages/internal-postcss-fix-relative-paths/src/fixtures/example-project/src/index.css
+++ b/packages/internal-postcss-fix-relative-paths/src/fixtures/example-project/src/index.css
@@ -1,3 +1,4 @@
 @content "./**/*.ts";
+@content "!./**/*.ts";
 @plugin "./plugin.js";
 @plugin "./what\"s-this.js";
diff --git a/packages/internal-postcss-fix-relative-paths/src/index.test.ts b/packages/internal-postcss-fix-relative-paths/src/index.test.ts
index c66699c6582c..5c8f7a58ba99 100644
--- a/packages/internal-postcss-fix-relative-paths/src/index.test.ts
+++ b/packages/internal-postcss-fix-relative-paths/src/index.test.ts
@@ -1,4 +1,5 @@
 import fs from 'node:fs'
+import path from 'node:path'
 import postcss from 'postcss'
 import atImport from 'postcss-import'
 import { describe, expect, test } from 'vitest'
@@ -6,7 +7,7 @@ import fixRelativePathsPlugin from '.'
 
 describe('fixRelativePathsPlugin', () => {
   test('rewrites @content and @plugin to be relative to the initial css file', async () => {
-    let cssPath = `${__dirname}/fixtures/external-import/src/index.css`
+    let cssPath = path.join(__dirname, 'fixtures', 'external-import', 'src', 'index.css')
     let css = fs.readFileSync(cssPath, 'utf-8')
 
     let processor = postcss([atImport(), fixRelativePathsPlugin()])
@@ -15,13 +16,14 @@ describe('fixRelativePathsPlugin', () => {
 
     expect(result.css.trim()).toMatchInlineSnapshot(`
       "@content "../../example-project/src/**/*.ts";
+      @content "!../../example-project/src/**/*.ts";
       @plugin "../../example-project/src/plugin.js";
       @plugin "../../example-project/src/what\\"s-this.js";"
     `)
   })
 
   test('should not rewrite non-relative paths', async () => {
-    let cssPath = `${__dirname}/fixtures/external-import/src/invalid.css`
+    let cssPath = path.join(__dirname, 'fixtures', 'external-import', 'src', 'invalid.css')
     let css = fs.readFileSync(cssPath, 'utf-8')
 
     let processor = postcss([atImport(), fixRelativePathsPlugin()])
@@ -37,7 +39,7 @@ describe('fixRelativePathsPlugin', () => {
   })
 
   test('should return relative paths even if the file is resolved in the same basedir as the root stylesheet', async () => {
-    let cssPath = `${__dirname}/fixtures/external-import/src/plugins-in-root.css`
+    let cssPath = path.join(__dirname, 'fixtures', 'external-import', 'src', 'plugins-in-root.css')
     let css = fs.readFileSync(cssPath, 'utf-8')
 
     let processor = postcss([atImport(), fixRelativePathsPlugin()])
diff --git a/packages/internal-postcss-fix-relative-paths/src/index.ts b/packages/internal-postcss-fix-relative-paths/src/index.ts
index 0193284fe197..5eb20b05ce27 100644
--- a/packages/internal-postcss-fix-relative-paths/src/index.ts
+++ b/packages/internal-postcss-fix-relative-paths/src/index.ts
@@ -1,5 +1,6 @@
 import path from 'node:path'
-import type { AtRule, Container, Plugin } from 'postcss'
+import type { AtRule, Plugin } from 'postcss'
+import { normalizePath } from './normalize-path'
 
 const SINGLE_QUOTE = "'"
 const DOUBLE_QUOTE = '"'
@@ -9,12 +10,12 @@ export default function fixRelativePathsPlugin(): Plugin {
   let touched: WeakSet<AtRule> = new WeakSet()
 
   function fixRelativePath(atRule: AtRule) {
-    let rootPath = getRoot(atRule)?.source?.input.file
+    let rootPath = atRule.root().source?.input.file
     if (!rootPath) {
       return
     }
 
-    let inputFilePath = atRule?.source?.input.file
+    let inputFilePath = atRule.source?.input.file
     if (!inputFilePath) {
       return
     }
@@ -34,15 +35,24 @@ export default function fixRelativePathsPlugin(): Plugin {
     if (!quote) {
       return
     }
-    let content = atRule.params.slice(1, -1)
+    let glob = atRule.params.slice(1, -1)
+
+    // Handle eventual negative rules. We only support one level of negation.
+    let negativePrefix = ''
+    if (glob.startsWith('!')) {
+      glob = glob.slice(1)
+      negativePrefix = '!'
+    }
 
     // We only want to rewrite relative paths.
-    if (!content.startsWith('./') && !content.startsWith('../')) {
+    if (!glob.startsWith('./') && !glob.startsWith('../')) {
       return
     }
 
-    let rulePath = path.posix.join(path.posix.dirname(inputFilePath), content)
-    let relative = path.posix.relative(path.posix.dirname(rootPath), rulePath)
+    let absoluteGlob = path.posix.join(normalizePath(path.dirname(inputFilePath)), glob)
+    let absoluteRootPosixPath = path.posix.dirname(normalizePath(rootPath))
+
+    let relative = path.posix.relative(absoluteRootPosixPath, absoluteGlob)
 
     // If the path points to a file in the same directory, `path.relative` will
     // remove the leading `./` and we need to add it back in order to still
@@ -51,17 +61,10 @@ export default function fixRelativePathsPlugin(): Plugin {
       relative = './' + relative
     }
 
-    atRule.params = quote + relative + quote
+    atRule.params = quote + negativePrefix + relative + quote
     touched.add(atRule)
   }
 
-  function getRoot(node: AtRule | Container | undefined): Container | undefined {
-    if (node?.parent) {
-      return getRoot(node.parent as Container)
-    }
-    return node
-  }
-
   return {
     postcssPlugin: 'tailwindcss-postcss-fix-relative-paths',
     AtRule: {
diff --git a/packages/internal-postcss-fix-relative-paths/src/normalize-path.ts b/packages/internal-postcss-fix-relative-paths/src/normalize-path.ts
new file mode 100644
index 000000000000..a8184ef2317c
--- /dev/null
+++ b/packages/internal-postcss-fix-relative-paths/src/normalize-path.ts
@@ -0,0 +1,47 @@
+// Inlined version of `normalize-path` <https://github.com/jonschlinkert/normalize-path>
+// Copyright (c) 2014-2018, Jon Schlinkert.
+// Released under the MIT License.
+function normalizePathBase(path: string, stripTrailing?: boolean) {
+  if (typeof path !== 'string') {
+    throw new TypeError('expected path to be a string')
+  }
+
+  if (path === '\\' || path === '/') return '/'
+
+  var len = path.length
+  if (len <= 1) return path
+
+  // ensure that win32 namespaces has two leading slashes, so that the path is
+  // handled properly by the win32 version of path.parse() after being normalized
+  // https://msdn.microsoft.com/library/windows/desktop/aa365247(v=vs.85).aspx#namespaces
+  var prefix = ''
+  if (len > 4 && path[3] === '\\') {
+    var ch = path[2]
+    if ((ch === '?' || ch === '.') && path.slice(0, 2) === '\\\\') {
+      path = path.slice(2)
+      prefix = '//'
+    }
+  }
+
+  var segs = path.split(/[/\\]+/)
+  if (stripTrailing !== false && segs[segs.length - 1] === '') {
+    segs.pop()
+  }
+  return prefix + segs.join('/')
+}
+
+export function normalizePath(originalPath: string) {
+  let normalized = normalizePathBase(originalPath)
+
+  // Make sure Windows network share paths are normalized properly
+  // They have to begin with two slashes or they won't resolve correctly
+  if (
+    originalPath.startsWith('\\\\') &&
+    normalized.startsWith('/') &&
+    !normalized.startsWith('//')
+  ) {
+    return `/${normalized}`
+  }
+
+  return normalized
+}