diff --git a/CHANGELOG.md b/CHANGELOG.md
index 261ecb8e503f..635f62f7288f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - _Experimental_: Add `any-pointer-none`, `any-pointer-coarse`, and `any-pointer-fine` variants ([#16941](https://github.com/tailwindlabs/tailwindcss/pull/16941))
 - _Experimental_: Add `user-valid` and `user-invalid` variants ([#12370](https://github.com/tailwindlabs/tailwindcss/pull/12370))
 - _Experimental_: Add `wrap-anywhere`, `wrap-break-word`, and `wrap-normal` utilities ([#12128](https://github.com/tailwindlabs/tailwindcss/pull/12128))
+- _Experimental_: Add `@source inline(…)` ([#17147](https://github.com/tailwindlabs/tailwindcss/pull/17147))
 
 ### Fixed
 
diff --git a/packages/tailwindcss/src/feature-flags.ts b/packages/tailwindcss/src/feature-flags.ts
index d3278905e8d2..404353be2804 100644
--- a/packages/tailwindcss/src/feature-flags.ts
+++ b/packages/tailwindcss/src/feature-flags.ts
@@ -2,5 +2,6 @@ export const enableDetailsContent = process.env.FEATURES_ENV !== 'stable'
 export const enableInvertedColors = process.env.FEATURES_ENV !== 'stable'
 export const enablePointerVariants = process.env.FEATURES_ENV !== 'stable'
 export const enableScripting = process.env.FEATURES_ENV !== 'stable'
+export const enableSourceInline = process.env.FEATURES_ENV !== 'stable'
 export const enableUserValid = process.env.FEATURES_ENV !== 'stable'
 export const enableWrapAnywhere = process.env.FEATURES_ENV !== 'stable'
diff --git a/packages/tailwindcss/src/index.test.ts b/packages/tailwindcss/src/index.test.ts
index c233541538d6..4779e6c18e65 100644
--- a/packages/tailwindcss/src/index.test.ts
+++ b/packages/tailwindcss/src/index.test.ts
@@ -3194,6 +3194,185 @@ describe('@source', () => {
       { pattern: './php/secr3t/smarty.php', base: '/root' },
     ])
   })
+
+  describe('@source inline(…)', () => {
+    test('always includes the candidate', async () => {
+      let { build } = await compile(
+        css`
+          @source inline("underline");
+          @tailwind utilities;
+        `,
+        { base: '/root' },
+      )
+
+      expect(build([])).toMatchInlineSnapshot(`
+        ".underline {
+          text-decoration-line: underline;
+        }
+        "
+      `)
+    })
+
+    test('applies brace expansion', async () => {
+      let { build } = await compile(
+        css`
+          @theme {
+            --color-red-50: oklch(0.971 0.013 17.38);
+            --color-red-100: oklch(0.936 0.032 17.717);
+            --color-red-200: oklch(0.885 0.062 18.334);
+            --color-red-300: oklch(0.808 0.114 19.571);
+            --color-red-400: oklch(0.704 0.191 22.216);
+            --color-red-500: oklch(0.637 0.237 25.331);
+            --color-red-600: oklch(0.577 0.245 27.325);
+            --color-red-700: oklch(0.505 0.213 27.518);
+            --color-red-800: oklch(0.444 0.177 26.899);
+            --color-red-900: oklch(0.396 0.141 25.723);
+            --color-red-950: oklch(0.258 0.092 26.042);
+          }
+          @source inline("bg-red-{50,{100..900..100},950}");
+          @tailwind utilities;
+        `,
+        { base: '/root' },
+      )
+
+      expect(build([])).toMatchInlineSnapshot(`
+        ":root, :host {
+          --color-red-50: oklch(0.971 0.013 17.38);
+          --color-red-100: oklch(0.936 0.032 17.717);
+          --color-red-200: oklch(0.885 0.062 18.334);
+          --color-red-300: oklch(0.808 0.114 19.571);
+          --color-red-400: oklch(0.704 0.191 22.216);
+          --color-red-500: oklch(0.637 0.237 25.331);
+          --color-red-600: oklch(0.577 0.245 27.325);
+          --color-red-700: oklch(0.505 0.213 27.518);
+          --color-red-800: oklch(0.444 0.177 26.899);
+          --color-red-900: oklch(0.396 0.141 25.723);
+          --color-red-950: oklch(0.258 0.092 26.042);
+        }
+        .bg-red-50 {
+          background-color: var(--color-red-50);
+        }
+        .bg-red-100 {
+          background-color: var(--color-red-100);
+        }
+        .bg-red-200 {
+          background-color: var(--color-red-200);
+        }
+        .bg-red-300 {
+          background-color: var(--color-red-300);
+        }
+        .bg-red-400 {
+          background-color: var(--color-red-400);
+        }
+        .bg-red-500 {
+          background-color: var(--color-red-500);
+        }
+        .bg-red-600 {
+          background-color: var(--color-red-600);
+        }
+        .bg-red-700 {
+          background-color: var(--color-red-700);
+        }
+        .bg-red-800 {
+          background-color: var(--color-red-800);
+        }
+        .bg-red-900 {
+          background-color: var(--color-red-900);
+        }
+        .bg-red-950 {
+          background-color: var(--color-red-950);
+        }
+        "
+      `)
+    })
+
+    test('adds multiple inline sources separated by spaces', async () => {
+      let { build } = await compile(
+        css`
+          @theme {
+            --color-red-100: oklch(0.936 0.032 17.717);
+            --color-red-200: oklch(0.885 0.062 18.334);
+          }
+          @source inline("block bg-red-{100..200..100}");
+          @tailwind utilities;
+        `,
+        { base: '/root' },
+      )
+
+      expect(build([])).toMatchInlineSnapshot(`
+        ":root, :host {
+          --color-red-100: oklch(0.936 0.032 17.717);
+          --color-red-200: oklch(0.885 0.062 18.334);
+        }
+        .block {
+          display: block;
+        }
+        .bg-red-100 {
+          background-color: var(--color-red-100);
+        }
+        .bg-red-200 {
+          background-color: var(--color-red-200);
+        }
+        "
+      `)
+    })
+
+    test('ignores invalid inline candidates', async () => {
+      let { build } = await compile(
+        css`
+          @source inline("my-cucumber");
+          @tailwind utilities;
+        `,
+        { base: '/root' },
+      )
+
+      expect(build([])).toMatchInlineSnapshot(`""`)
+    })
+
+    test('can be negated', async () => {
+      let { build } = await compile(
+        css`
+          @theme {
+            --breakpoint-sm: 40rem;
+            --breakpoint-md: 48rem;
+            --breakpoint-lg: 64rem;
+            --breakpoint-xl: 80rem;
+            --breakpoint-2xl: 96rem;
+          }
+          @source not inline("container");
+          @tailwind utilities;
+        `,
+        { base: '/root' },
+      )
+
+      expect(build(['container'])).toMatchInlineSnapshot(`""`)
+    })
+
+    test('applies brace expansion to negated sources', async () => {
+      let { build } = await compile(
+        css`
+          @theme {
+            --color-red-50: oklch(0.971 0.013 17.38);
+            --color-red-100: oklch(0.936 0.032 17.717);
+            --color-red-200: oklch(0.885 0.062 18.334);
+            --color-red-300: oklch(0.808 0.114 19.571);
+            --color-red-400: oklch(0.704 0.191 22.216);
+            --color-red-500: oklch(0.637 0.237 25.331);
+            --color-red-600: oklch(0.577 0.245 27.325);
+            --color-red-700: oklch(0.505 0.213 27.518);
+            --color-red-800: oklch(0.444 0.177 26.899);
+            --color-red-900: oklch(0.396 0.141 25.723);
+            --color-red-950: oklch(0.258 0.092 26.042);
+          }
+          @source not inline("bg-red-{50,{100..900..100},950}");
+          @tailwind utilities;
+        `,
+        { base: '/root' },
+      )
+
+      expect(build(['bg-red-500', 'bg-red-700'])).toMatchInlineSnapshot(`""`)
+    })
+  })
 })
 
 describe('@custom-variant', () => {
diff --git a/packages/tailwindcss/src/index.ts b/packages/tailwindcss/src/index.ts
index 65d1379da1c6..ddcd17ae6565 100644
--- a/packages/tailwindcss/src/index.ts
+++ b/packages/tailwindcss/src/index.ts
@@ -26,8 +26,10 @@ import { applyVariant, compileCandidates } from './compile'
 import { substituteFunctions } from './css-functions'
 import * as CSS from './css-parser'
 import { buildDesignSystem, type DesignSystem } from './design-system'
+import { enableSourceInline } from './feature-flags'
 import { Theme, ThemeOptions } from './theme'
 import { createCssUtility } from './utilities'
+import { expand } from './utils/brace-expansion'
 import { escape, unescape } from './utils/escape'
 import { segment } from './utils/segment'
 import { compoundsForSelectors, IS_VALID_VARIANT_NAME } from './variants'
@@ -127,6 +129,8 @@ async function parseCss(
   let utilitiesNode = null as AtRule | null
   let variantNodes: AtRule[] = []
   let globs: { base: string; pattern: string }[] = []
+  let inlineCandidates: string[] = []
+  let ignoredCandidates: string[] = []
   let root = null as Root
 
   // Handle at-rules
@@ -208,7 +212,22 @@ async function parseCss(
         throw new Error('`@source` cannot be nested.')
       }
 
+      let not = false
+      let inline = false
       let path = node.params
+
+      if (enableSourceInline) {
+        if (path[0] === 'n' && path.startsWith('not ')) {
+          not = true
+          path = path.slice(4)
+        }
+
+        if (path[0] === 'i' && path.startsWith('inline(')) {
+          inline = true
+          path = path.slice(7, -1)
+        }
+      }
+
       if (
         (path[0] === '"' && path[path.length - 1] !== '"') ||
         (path[0] === "'" && path[path.length - 1] !== "'") ||
@@ -216,7 +235,20 @@ async function parseCss(
       ) {
         throw new Error('`@source` paths must be quoted.')
       }
-      globs.push({ base: context.base as string, pattern: path.slice(1, -1) })
+
+      let source = path.slice(1, -1)
+
+      if (enableSourceInline && inline) {
+        let destination = not ? ignoredCandidates : inlineCandidates
+        let sources = segment(source, ' ')
+        for (let source of sources) {
+          for (let candidate of expand(source)) {
+            destination.push(candidate)
+          }
+        }
+      } else {
+        globs.push({ base: context.base as string, pattern: source })
+      }
       replaceWith([])
       return
     }
@@ -505,6 +537,12 @@ async function parseCss(
     designSystem.important = important
   }
 
+  if (ignoredCandidates.length > 0) {
+    for (let candidate of ignoredCandidates) {
+      designSystem.invalidCandidates.add(candidate)
+    }
+  }
+
   // Apply hooks from backwards compatibility layer. This function takes a lot
   // of random arguments because it really just needs access to "the world" to
   // do whatever ungodly things it needs to do to make things backwards
@@ -603,6 +641,7 @@ async function parseCss(
     root,
     utilitiesNode,
     features,
+    inlineCandidates,
   }
 }
 
@@ -615,7 +654,8 @@ export async function compileAst(
   features: Features
   build(candidates: string[]): AstNode[]
 }> {
-  let { designSystem, ast, globs, root, utilitiesNode, features } = await parseCss(input, opts)
+  let { designSystem, ast, globs, root, utilitiesNode, features, inlineCandidates } =
+    await parseCss(input, opts)
 
   if (process.env.NODE_ENV !== 'test') {
     ast.unshift(comment(`! tailwindcss v${version} | MIT License | https://tailwindcss.com `))
@@ -632,6 +672,14 @@ export async function compileAst(
   let allValidCandidates = new Set<string>()
   let compiled = null as AstNode[] | null
   let previousAstNodeCount = 0
+  let defaultDidChange = false
+
+  for (let candidate of inlineCandidates) {
+    if (!designSystem.invalidCandidates.has(candidate)) {
+      allValidCandidates.add(candidate)
+      defaultDidChange = true
+    }
+  }
 
   return {
     globs,
@@ -647,7 +695,8 @@ export async function compileAst(
         return compiled
       }
 
-      let didChange = false
+      let didChange = defaultDidChange
+      defaultDidChange = false
 
       // Add all new candidates unless we know that they are invalid.
       let prevSize = allValidCandidates.size
diff --git a/packages/tailwindcss/src/utils/brace-expansion.bench.ts b/packages/tailwindcss/src/utils/brace-expansion.bench.ts
new file mode 100644
index 000000000000..6a0e3d8fd900
--- /dev/null
+++ b/packages/tailwindcss/src/utils/brace-expansion.bench.ts
@@ -0,0 +1,14 @@
+// import braces from 'braces'
+import { bench } from 'vitest'
+import { expand } from './brace-expansion'
+
+const PATTERN =
+  '{{xs,sm,md,lg}:,}{border-{x,y,t,r,b,l,s,e},bg,text,cursor,accent}-{{red,orange,amber,yellow,lime,green,emerald,teal,cyan,sky,blue,indigo,violet,purple,fuchsia,pink,rose,slate,gray,zinc,neutral,stone}-{50,{100..900..100},950},black,white}{,/{0..100}}'
+
+// bench('braces', () => {
+//   void braces.expand(PATTERN)
+// })
+
+bench('./brace-expansion', () => {
+  void expand(PATTERN)
+})
diff --git a/packages/tailwindcss/src/utils/brace-expansion.test.ts b/packages/tailwindcss/src/utils/brace-expansion.test.ts
new file mode 100644
index 000000000000..f6d3d12f130a
--- /dev/null
+++ b/packages/tailwindcss/src/utils/brace-expansion.test.ts
@@ -0,0 +1,80 @@
+import { describe, expect, test } from 'vitest'
+import { expand } from './brace-expansion'
+
+describe('expand(…)', () => {
+  test.each([
+    ['a/b/c', ['a/b/c']],
+
+    // Groups
+    ['a/{x,y,z}/b', ['a/x/b', 'a/y/b', 'a/z/b']],
+    ['{a,b}/{x,y}', ['a/x', 'a/y', 'b/x', 'b/y']],
+    ['{{xs,sm,md,lg}:,}hidden', ['xs:hidden', 'sm:hidden', 'md:hidden', 'lg:hidden', 'hidden']],
+
+    // Numeric ranges
+    ['a/{0..5}/b', ['a/0/b', 'a/1/b', 'a/2/b', 'a/3/b', 'a/4/b', 'a/5/b']],
+    ['a/{-5..0}/b', ['a/-5/b', 'a/-4/b', 'a/-3/b', 'a/-2/b', 'a/-1/b', 'a/0/b']],
+    ['a/{0..-5}/b', ['a/0/b', 'a/-1/b', 'a/-2/b', 'a/-3/b', 'a/-4/b', 'a/-5/b']],
+
+    // Numeric range with padding
+    ['a/{00..05}/b', ['a/00/b', 'a/01/b', 'a/02/b', 'a/03/b', 'a/04/b', 'a/05/b']],
+    [
+      'a{001..9}b',
+      ['a001b', 'a002b', 'a003b', 'a004b', 'a005b', 'a006b', 'a007b', 'a008b', 'a009b'],
+    ],
+
+    // Numeric range with step
+    ['a/{0..5..2}/b', ['a/0/b', 'a/2/b', 'a/4/b']],
+    [
+      'bg-red-{100..900..100}',
+      [
+        'bg-red-100',
+        'bg-red-200',
+        'bg-red-300',
+        'bg-red-400',
+        'bg-red-500',
+        'bg-red-600',
+        'bg-red-700',
+        'bg-red-800',
+        'bg-red-900',
+      ],
+    ],
+
+    // Nested braces
+    ['a{b,c,/{x,y}}/e', ['ab/e', 'ac/e', 'a/x/e', 'a/y/e']],
+    ['a{b,c,/{x,y},{z,w}}/e', ['ab/e', 'ac/e', 'a/x/e', 'a/y/e', 'az/e', 'aw/e']],
+    ['a{b,c,/{x,y},{0..2}}/e', ['ab/e', 'ac/e', 'a/x/e', 'a/y/e', 'a0/e', 'a1/e', 'a2/e']],
+    [
+      'bg-red-{50,{100..900..100},950}',
+      [
+        'bg-red-50',
+        'bg-red-100',
+        'bg-red-200',
+        'bg-red-300',
+        'bg-red-400',
+        'bg-red-500',
+        'bg-red-600',
+        'bg-red-700',
+        'bg-red-800',
+        'bg-red-900',
+        'bg-red-950',
+      ],
+    ],
+
+    // Should not try to expand ranges with decimals
+    ['{1.1..2.2}', ['1.1..2.2']],
+  ])('should expand %s', (input, expected) => {
+    expect(expand(input).sort()).toEqual(expected.sort())
+  })
+
+  test('throws on unbalanced braces', () => {
+    expect(() => expand('a{b,c{d,e},{f,g}h}x{y,z')).toThrowErrorMatchingInlineSnapshot(
+      `[Error: The pattern \`x{y,z\` is not balanced.]`,
+    )
+  })
+
+  test('throws when step is set to zero', () => {
+    expect(() => expand('a{0..5..0}/b')).toThrowErrorMatchingInlineSnapshot(
+      `[Error: Step cannot be zero in sequence expansion.]`,
+    )
+  })
+})
diff --git a/packages/tailwindcss/src/utils/brace-expansion.ts b/packages/tailwindcss/src/utils/brace-expansion.ts
new file mode 100644
index 000000000000..95431d4c6704
--- /dev/null
+++ b/packages/tailwindcss/src/utils/brace-expansion.ts
@@ -0,0 +1,103 @@
+import { segment } from './segment'
+
+const NUMERICAL_RANGE = /^(-?\d+)\.\.(-?\d+)(?:\.\.(-?\d+))?$/
+
+export function expand(pattern: string): string[] {
+  let index = pattern.indexOf('{')
+  if (index === -1) return [pattern]
+
+  let result: string[] = []
+  let pre = pattern.slice(0, index)
+  let rest = pattern.slice(index)
+
+  // Find the matching closing brace
+  let depth = 0
+  let endIndex = rest.lastIndexOf('}')
+  for (let i = 0; i < rest.length; i++) {
+    let char = rest[i]
+    if (char === '{') {
+      depth++
+    } else if (char === '}') {
+      depth--
+      if (depth === 0) {
+        endIndex = i
+        break
+      }
+    }
+  }
+
+  if (endIndex === -1) {
+    throw new Error(`The pattern \`${pattern}\` is not balanced.`)
+  }
+
+  let inside = rest.slice(1, endIndex)
+  let post = rest.slice(endIndex + 1)
+  let parts: string[]
+
+  if (isSequence(inside)) {
+    parts = expandSequence(inside)
+  } else {
+    parts = segment(inside, ',')
+  }
+
+  parts = parts.flatMap((part) => expand(part))
+
+  let expandedTail = expand(post)
+
+  for (let tail of expandedTail) {
+    for (let part of parts) {
+      result.push(pre + part + tail)
+    }
+  }
+  return result
+}
+
+function isSequence(str: string): boolean {
+  return NUMERICAL_RANGE.test(str)
+}
+
+/**
+ * Expands a sequence string like "01..20" (optionally with a step).
+ */
+function expandSequence(seq: string): string[] {
+  let seqMatch = seq.match(NUMERICAL_RANGE)
+  if (!seqMatch) {
+    return [seq]
+  }
+  let [, start, end, stepStr] = seqMatch
+  let step = stepStr ? parseInt(stepStr, 10) : undefined
+  let result: string[] = []
+
+  if (/^-?\d+$/.test(start) && /^-?\d+$/.test(end)) {
+    let startNum = parseInt(start, 10)
+    let endNum = parseInt(end, 10)
+
+    // Determine padding length (if any) but don't count the sign as length
+    let padLength = Math.max(start.replace(/^-/, '').length, end.replace(/^-/, '').length)
+
+    if (step === undefined) {
+      step = startNum <= endNum ? 1 : -1
+    }
+    if (step === 0) {
+      throw new Error('Step cannot be zero in sequence expansion.')
+    }
+    if (step > 0) {
+      for (let i = startNum; i <= endNum; i += step) {
+        let numStr = i.toString()
+        if (numStr.length < padLength) {
+          numStr = numStr.padStart(padLength, '0')
+        }
+        result.push(numStr)
+      }
+    } else {
+      for (let i = startNum; i >= endNum; i += step) {
+        let numStr = i.toString()
+        if (numStr.length < padLength) {
+          numStr = numStr.padStart(padLength, '0')
+        }
+        result.push(numStr)
+      }
+    }
+  }
+  return result
+}