stylelint · ybiquitous · Aug 12, 2025 · Jul 22, 2025 · Jul 22, 2025 · Jul 22, 2025
diff --git a/.changeset/great-geese-wink.md b/.changeset/great-geese-wink.md
@@ -0,0 +1,5 @@
+---
+"stylelint": minor
+---
+
+Added: `rule-nesting-at-rule-required-list` rule
diff --git a/docs/user-guide/rules.md b/docs/user-guide/rules.md
@@ -197,6 +197,7 @@ Allow, disallow or require things with these `allowed-list`, `disallowed-list`,
 <!-- prettier-ignore-start -->
 | | | |
 | :-- | :-: | :-: |
+| [`rule-nesting-at-rule-required-list`](../../lib/rules/rule-nesting-at-rule-required-list/README.md)<br/>Require rules to be nested in specific at-rules. | | |
 | [`declaration-no-important`](../../lib/rules/declaration-no-important/README.md)<br/>Disallow `!important` within declarations. | | |
 | [`declaration-property-unit-allowed-list`](../../lib/rules/declaration-property-unit-allowed-list/README.md)<br/>Specify a list of allowed property and unit pairs within declarations. | | |
 | [`declaration-property-unit-disallowed-list`](../../lib/rules/declaration-property-unit-disallowed-list/README.md)<br/>Specify a list of disallowed property and unit pairs within declarations. | | |

diff --git a/lib/rules/index.cjs b/lib/rules/index.cjs
diff --git a/lib/rules/index.mjs b/lib/rules/index.mjs
@@ -98,6 +98,9 @@ const rules = {
 	get 'declaration-block-no-duplicate-properties'() {
 		return import('./declaration-block-no-duplicate-properties/index.mjs').then((m) => m.default);
 	},
+	get 'rule-nesting-at-rule-required-list'() {
+		return import('./rule-nesting-at-rule-required-list/index.mjs').then((m) => m.default);
+	},
 	get 'declaration-block-no-redundant-longhand-properties'() {
 		return import('./declaration-block-no-redundant-longhand-properties/index.mjs').then(
 			(m) => m.default,

diff --git a/lib/rules/rule-nesting-at-rule-required-list/README.md b/lib/rules/rule-nesting-at-rule-required-list/README.md
@@ -0,0 +1,61 @@
+# rule-nesting-at-rule-required-list
+
+Require rules to be nested in specific at-rules.
+
+<!-- prettier-ignore -->
+```css
+a { color: red; }
+/** ↑
+ * This rule */
+```
+
+## Options
+
+### `Array<string | RegExp>`
+
+Given:
+
+```json
+{
+  "rule-nesting-at-rule-required-list": ["layer"]
+}
+```
+
+The following patterns are considered problems:
+
+<!-- prettier-ignore -->
+```css
+a { color: red; }
+```
+
+<!-- prettier-ignore -->
+```css
+@media all {
+  a { color: red; }
+}
+```
+
+<!-- prettier-ignore -->
+```css
+a {
+  @layer {
+    color: red;
+  }
+}
+```
+
+The following patterns are _not_ considered problems:
+
+<!-- prettier-ignore -->
+```css
+@layer {
+  a { color: red; }
+}
+```
+
+<!-- prettier-ignore -->
+```css
+@font-face {
+  font-family: "foo";
+}
+```
diff --git a/lib/rules/rule-nesting-at-rule-required-list/__tests__/index.mjs b/lib/rules/rule-nesting-at-rule-required-list/__tests__/index.mjs
@@ -0,0 +1,151 @@
+import rule from '../index.mjs';
+const { messages, ruleName } = rule;
+
+testRule({
+	ruleName,
+	config: ['layer', '/^s/'],
+
+	accept: [
+		{
+			code: '@layer { a { color: red; } }',
+			description: 'rule within @layer at-rule',
+		},
+		{
+			code: '@supports (color: red) { a { color: red; } }',
+			description: 'rule within @supports at-rule (matches regex)',
+		},
+		{
+			code: '@scope (a) { a { color: red; } }',
+			description: 'rule within @scope at-rule (matches regex)',
+		},
+		{
+			code: '@media all {}',
+			description: 'empty at-rule',
+		},
+		{
+			code: '@layer { @media all { a { color: red; } } }',
+			description: 'rule within nested required at-rule',
+		},
+		{
+			code: '@font-face { font-family: "foo"; }',
+			description: 'at-rule descriptor',
+		},
+	],
+
+	reject: [
+		{
+			code: 'a { color: red; }',
+			description: 'rule without required at-rule',
+			message: messages.expected('layer, /^s/'),
+			line: 1,
+			column: 1,
+			endLine: 1,
+			endColumn: 18,
+		},
+		{
+			code: '@media all { a { color: red; } }',
+			description: 'rule within non-required at-rule',
+			message: messages.expected('layer, /^s/'),
+			line: 1,
+			column: 14,
+			endLine: 1,
+			endColumn: 31,
+		},
+		{
+			code: 'a { @layer { color: red; } }',
+			description: 'rule with nested declarations rule',
+			message: messages.expected('layer, /^s/'),
+			line: 1,
+			column: 1,
+			endLine: 1,
+			endColumn: 29,
+		},
+	],
+});
+
+testRule({
+	ruleName,
+	config: ['layer'],
+
+	accept: [
+		{
+			code: '@layer { a { color: red; } }',
+			description: 'rule within @layer at-rule',
+		},
+		{
+			code: '@font-face { font-family: "foo"; }',
+			description: 'at-rule descriptor',
+		},
+	],
+
+	reject: [
+		{
+			code: 'a { color: red; }',
+			description: 'rule without required at-rule',
+			message: messages.expected('layer'),
+			line: 1,
+			column: 1,
+			endLine: 1,
+			endColumn: 18,
+		},
+		{
+			code: '@supports (color: red) { a { color: red; } }',
+			description: 'rule within non-required at-rule',
+			message: messages.expected('layer'),
+			line: 1,
+			column: 26,
+			endLine: 1,
+			endColumn: 43,
+		},
+		{
+			code: 'a { @layer { color: red; } }',
+			description: 'rule with nested declarations rule',
+			message: messages.expected('layer'),
+			line: 1,
+			column: 1,
+			endLine: 1,
+			endColumn: 29,
+		},
+	],
+});
+
+testRule({
+	ruleName,
+	config: ['/^s/'],
+
+	accept: [
+		{
+			code: '@supports (color: red) { a { color: red; } }',
+			description: 'rule within @supports at-rule (matches regex)',
+		},
+		{
+			code: '@scope (a) { a { color: red; } }',
+			description: 'rule within @scope at-rule (matches regex)',
+		},
+		{
+			code: '@font-face { font-family: "foo"; }',
+			description: 'at-rule descriptor',
+		},
+	],
+
+	reject: [
+		{
+			code: 'a { color: red; }',
+			description: 'rule without required at-rule',
+			message: messages.expected('/^s/'),
+			line: 1,
+			column: 1,
+			endLine: 1,
+			endColumn: 18,
+		},
+		{
+			code: '@layer { a { color: red; } }',
+			description: 'rule within non-matching at-rule',
+			message: messages.expected('/^s/'),
+			line: 1,
+			column: 10,
+			endLine: 1,
+			endColumn: 27,
+		},
+	],
+});
diff --git a/lib/rules/rule-nesting-at-rule-required-list/index.cjs b/lib/rules/rule-nesting-at-rule-required-list/index.cjs