diff --git a/CHANGELOG.md b/CHANGELOG.md
index 092cc699f..26a888572 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Make `content` optional for presets in TypeScript types ([#11730](https://github.com/tailwindlabs/tailwindcss/pull/11730))
 - Handle variable colors that have variable fallback values ([#12049](https://github.com/tailwindlabs/tailwindcss/pull/12049))
 - Batch reading content files to prevent `too many open files` error ([#12079](https://github.com/tailwindlabs/tailwindcss/pull/12079))
+- Skip over classes inside `:not(…)` when nested in an at-rule ([#12105](https://github.com/tailwindlabs/tailwindcss/pull/12105))
 
 ## [3.3.3] - 2023-07-13
 
diff --git a/src/lib/setupContextUtils.js b/src/lib/setupContextUtils.js
index 4d85e9d8c..b173d419f 100644
--- a/src/lib/setupContextUtils.js
+++ b/src/lib/setupContextUtils.js
@@ -148,43 +148,45 @@ function getClasses(selector, mutate) {
   return parser.transformSync(selector)
 }
 
+/**
+ * Ignore everything inside a :not(...). This allows you to write code like
+ * `div:not(.foo)`. If `.foo` is never found in your code, then we used to
+ * not generated it. But now we will ignore everything inside a `:not`, so
+ * that it still gets generated.
+ *
+ * @param {selectorParser.Root} selectors
+ */
+function ignoreNot(selectors) {
+  selectors.walkPseudos((pseudo) => {
+    if (pseudo.value === ':not') {
+      pseudo.remove()
+    }
+  })
+}
+
 function extractCandidates(node, state = { containsNonOnDemandable: false }, depth = 0) {
   let classes = []
+  let selectors = []
 
-  // Handle normal rules
   if (node.type === 'rule') {
-    // Ignore everything inside a :not(...). This allows you to write code like
-    // `div:not(.foo)`. If `.foo` is never found in your code, then we used to
-    // not generated it. But now we will ignore everything inside a `:not`, so
-    // that it still gets generated.
-    function ignoreNot(selectors) {
-      selectors.walkPseudos((pseudo) => {
-        if (pseudo.value === ':not') {
-          pseudo.remove()
-        }
-      })
-    }
-
-    for (let selector of node.selectors) {
-      let classCandidates = getClasses(selector, ignoreNot)
-      // At least one of the selectors contains non-"on-demandable" candidates.
-      if (classCandidates.length === 0) {
-        state.containsNonOnDemandable = true
-      }
-
-      for (let classCandidate of classCandidates) {
-        classes.push(classCandidate)
-      }
-    }
+    // Handle normal rules
+    selectors.push(...node.selectors)
+  } else if (node.type === 'atrule') {
+    // Handle at-rules (which contains nested rules)
+    node.walkRules((rule) => selectors.push(...rule.selectors))
   }
 
-  // Handle at-rules (which contains nested rules)
-  else if (node.type === 'atrule') {
-    node.walkRules((rule) => {
-      for (let classCandidate of rule.selectors.flatMap((selector) => getClasses(selector))) {
-        classes.push(classCandidate)
-      }
-    })
+  for (let selector of selectors) {
+    let classCandidates = getClasses(selector, ignoreNot)
+
+    // At least one of the selectors contains non-"on-demandable" candidates.
+    if (classCandidates.length === 0) {
+      state.containsNonOnDemandable = true
+    }
+
+    for (let classCandidate of classCandidates) {
+      classes.push(classCandidate)
+    }
   }
 
   if (depth === 0) {
diff --git a/tests/basic-usage.test.js b/tests/basic-usage.test.js
index 53c2a4418..66a5c67d4 100644
--- a/tests/basic-usage.test.js
+++ b/tests/basic-usage.test.js
@@ -2,7 +2,7 @@ import fs from 'fs'
 import path from 'path'
 import { crosscheck, run, html, css, defaults } from './util/run'
 
-crosscheck(({ stable, oxide }) => {
+crosscheck(({ stable, oxide, engine }) => {
   test('basic usage', () => {
     let config = {
       content: [
@@ -1017,4 +1017,98 @@ crosscheck(({ stable, oxide }) => {
       }
     `)
   })
+
+  test('detects quoted arbitrary values containing a slash', async () => {
+    let config = {
+      content: [
+        {
+          raw: html`<div class="group-[[href^='/']]:hidden"></div>`,
+        },
+      ],
+    }
+
+    let input = css`
+      @tailwind utilities;
+    `
+
+    let result = await run(input, config)
+
+    expect(result.css).toMatchFormattedCss(
+      engine.oxide
+        ? css`
+            .group[href^='/'] .group-\[\[href\^\=\'\/\'\]\]\:hidden {
+              display: none;
+            }
+          `
+        : css`
+            .hidden,
+            .group[href^='/'] .group-\[\[href\^\=\'\/\'\]\]\:hidden {
+              display: none;
+            }
+          `
+    )
+  })
+
+  test('handled quoted arbitrary values containing escaped spaces', async () => {
+    let config = {
+      content: [
+        {
+          raw: html`<div class="group-[[href^='_bar']]:hidden"></div>`,
+        },
+      ],
+    }
+
+    let input = css`
+      @tailwind utilities;
+    `
+
+    let result = await run(input, config)
+
+    expect(result.css).toMatchFormattedCss(
+      engine.oxide
+        ? css`
+            .group[href^=' bar'] .group-\[\[href\^\=\'_bar\'\]\]\:hidden {
+              display: none;
+            }
+          `
+        : css`
+            .hidden,
+            .group[href^=' bar'] .group-\[\[href\^\=\'_bar\'\]\]\:hidden {
+              display: none;
+            }
+          `
+    )
+  })
+
+  test('Skips classes inside :not() when nested inside an at-rule', async () => {
+    let config = {
+      content: [
+        {
+          raw: html` <div class="disabled !disabled"></div> `,
+        },
+      ],
+      corePlugins: { preflight: false },
+      plugins: [
+        function ({ addUtilities }) {
+          addUtilities({
+            '.hand:not(.disabled)': {
+              '@supports (cursor: pointer)': {
+                cursor: 'pointer',
+              },
+            },
+          })
+        },
+      ],
+    }
+
+    let input = css`
+      @tailwind utilities;
+    `
+
+    // We didn't find the hand class therefore
+    // nothing should be generated
+    let result = await run(input, config)
+
+    expect(result.css).toMatchFormattedCss(css``)
+  })
 })