diff --git a/packages/css-syntax-patches-for-csstree/CHANGELOG.md b/packages/css-syntax-patches-for-csstree/CHANGELOG.md
index d233ea481..847a0f286 100644
--- a/packages/css-syntax-patches-for-csstree/CHANGELOG.md
+++ b/packages/css-syntax-patches-for-csstree/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changes to CSS Syntax Patches For CSSTree
 
+### Unreleased (patch)
+
+- Fixed missing `container-query` type definition in patch output
+
 ### 1.1.3
 
 _April 12, 2026_
diff --git a/packages/css-syntax-patches-for-csstree/dist/index.json b/packages/css-syntax-patches-for-csstree/dist/index.json
index 79bc0cc35..84a67a63e 100644
--- a/packages/css-syntax-patches-for-csstree/dist/index.json
+++ b/packages/css-syntax-patches-for-csstree/dist/index.json
@@ -435,6 +435,7 @@
 		"types": {
 			"dashed-ident": "<custom-property-name>",
 			"unicode-range-token": "<urange>",
+			"container-query": "not <query-in-parens> | <query-in-parens> [ [ and <query-in-parens> ]* | [ or <query-in-parens> ]* ]",
 			"alpha()": "alpha( [ from <color> ] [ / [ <alpha-value> | alpha | none ] ]? )",
 			"an+b": "odd | even | <integer> | <n-dimension> | '+'? n | -n | <ndashdigit-dimension> | '+'? <ndashdigit-ident> | <dashndashdigit-ident> | <n-dimension> <signed-integer> | '+'? n <signed-integer> | -n <signed-integer> | <ndash-dimension> <signless-integer> | '+'? n- <signless-integer> | -n- <signless-integer> | <n-dimension> [ '+' | '-' ] <signless-integer> | '+'? n [ '+' | '-' ] <signless-integer> | -n [ '+' | '-' ] <signless-integer>",
 			"anchored-feature": "fallback : <'position-try-fallbacks'>",
diff --git a/packages/css-syntax-patches-for-csstree/scripts/apply-patches.mjs b/packages/css-syntax-patches-for-csstree/scripts/apply-patches.mjs
index ad169a672..88ea835cf 100644
--- a/packages/css-syntax-patches-for-csstree/scripts/apply-patches.mjs
+++ b/packages/css-syntax-patches-for-csstree/scripts/apply-patches.mjs
@@ -108,6 +108,7 @@ export function apply_patches(patches, onto) {
 	// Manual patches to smooth over compat between csstree and webref/css
 	types['dashed-ident'] = '<custom-property-name>';
 	types['unicode-range-token'] = '<urange>';
+	types['container-query'] = 'not <query-in-parens> | <query-in-parens> [ [ and <query-in-parens> ]* | [ or <query-in-parens> ]* ]';
 
 	for (const [name, definition] of Object.entries(onto.types)) {
 		const patch = patches.types[name];
diff --git a/packages/css-syntax-patches-for-csstree/tests/container-query.test.mjs b/packages/css-syntax-patches-for-csstree/tests/container-query.test.mjs
new file mode 100644
index 000000000..751399908
--- /dev/null
+++ b/packages/css-syntax-patches-for-csstree/tests/container-query.test.mjs
@@ -0,0 +1,26 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import fs from 'node:fs/promises';
+import path from 'path';
+import { fork, parse } from 'css-tree';
+
+const patches = JSON.parse(await fs.readFile(path.join('dist', 'index.json'), 'utf-8')).next;
+
+test('container-query type is defined in patch output', () => {
+	assert.ok(
+		patches.types['container-query'],
+		'container-query must be in patch output because container-condition and query-in-parens reference it',
+	);
+});
+
+test('@container prelude validates without error', () => {
+	const forkedLexer = fork({
+		atrules: patches.atrules,
+		properties: patches.properties,
+		types: patches.types,
+	}).lexer;
+
+	const prelude = parse('(min-width: 768px)', { context: 'atrulePrelude', atrule: 'container' });
+	const result = forkedLexer.matchAtrulePrelude('container', prelude);
+	assert.equal(result.error, null, `should validate @container prelude, got: ${result.error?.message}`);
+});