diff --git a/.bin/test-tape.js b/.bin/test-tape.js
index 43d99fa..8e72830 100644
--- a/.bin/test-tape.js
+++ b/.bin/test-tape.js
@@ -21,10 +21,8 @@ export default async function tape() {
 	failures += await test('ignores invalid entries', { basename: 'ignore' })
 	failures += await test('supports complex entries', { basename: 'complex' })
 	failures += await test('supports all spec examples', { basename: 'spec-examples' })
-	failures += await test('supports spec compliant mixing of nested rules and declarations', { basename: 'mixing-nested-rules-and-declarations-spec' })
-	failures += await test('supports legacy mixing of nested rules and declarations', { basename: 'mixing-nested-rules-and-declarations-legacy', pluginOptions: { allowDeclarationsAfterNestedRules: true } })
 
-	let mixinPlugin = () => {
+	let mixinPluginRule = () => {
 		return {
 			postcssPlugin: 'mixin',
 			AtRule: {
@@ -34,20 +32,35 @@ export default async function tape() {
 			},
 		}
 	}
-	mixinPlugin.postcss = true
-	failures += await test('supports other visitors', { basename: 'mixin' }, mixinPlugin)
+
+	mixinPluginRule.postcss = true
+	failures += await test('supports other visitors (mixin rule)', { basename: 'mixin-rule' }, mixinPluginRule)
+
+	let mixinPluginDeclaration = () => {
+		return {
+			postcssPlugin: 'mixin',
+			AtRule: {
+				mixin(node) {
+					node.replaceWith('color: blue;')
+				},
+			},
+		}
+	}
+
+	mixinPluginDeclaration.postcss = true
+	failures += await test('supports other visitors (mixin declaration)', { basename: 'mixin-declaration' }, mixinPluginDeclaration)
 
 	return failures === 0
 }
 
 async function test(name, init, ...plugins) {
-	const { basename, pluginOptions } = Object(init)
+	const { basename } = Object(init)
 
 	let sourceUrl = new URL(`test/${basename}.css`, workingUrl)
 	let expectUrl = new URL(`test/${basename}.expect.css`, workingUrl)
 	let resultUrl = new URL(`test/${basename}.result.css`, workingUrl)
 
-	plugins.unshift(plugin(pluginOptions))
+	plugins.unshift(plugin())
 
 	let sourceCss = await fs.readFile(sourceUrl, 'utf8')
 	let expectCss = await fs.readFile(expectUrl, 'utf8')
diff --git a/README.md b/README.md
index f90c941..039a14e 100644
--- a/README.md
+++ b/README.md
@@ -71,65 +71,6 @@ import postcssNesting from "https://deno.land/x/postcss_nesting/mod.js";
 await postcss([postcssNesting]).process(YOUR_CSS /*, processOptions */);
 ```
 
-## Options
-
-### allowDeclarationsAfterNestedRules
-
-The [specification](https://www.w3.org/TR/css-nesting-1/#mixing) does not allow declarations after nested rules.
-This was previously supported by this plugin and can be re-enabled with `allowDeclarationsAfterNestedRules`.
-
-Before :
-
-```css
-a {
-  color: red;
-
-  & b {
-    color: white;
-  }
-
-  padding: 20px;
-}
-```
-
-After **without** the option :
-
-```js
-postcssNesting()
-```
-
-```css
-a {
-  color: red;
-}
-
-a b {
-  color: white;
-}
-```
-
-After **with** the option :
-
-```js
-postcssNesting({
-  allowDeclarationsAfterNestedRules: true
-})
-```
-
-```css
-a {
-  color: red;
-}
-
-a b {
-  color: white;
-}
-
-a {
-  padding: 20px;
-}
-```
-
 [cli-img]: https://img.shields.io/travis/csstools/postcss-nesting.svg
 [cli-url]: https://travis-ci.org/csstools/postcss-nesting
 [css-img]: https://cssdb.org/badge/nesting-rules.svg
diff --git a/src/index.js b/src/index.js
index e7c6a73..f984cac 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,19 +1,12 @@
-import ensureCorrectMixingOfNestingRulesAndDeclarations from './lib/mixing-nesting-rules-and-declarations.js'
 import walk from './lib/walk.js'
 
 /**
- * @param {{allowDeclarationsAfterNestedRules?: boolean}} opts
  * @returns {import('postcss').Plugin}
  */
-export default function postcssNesting(opts) {
-	const allowDeclarationsAfterNestedRules = Object(opts).allowDeclarationsAfterNestedRules || false
-
+export default function postcssNesting() {
 	return {
 		postcssPlugin: 'postcss-nesting',
 		Rule(rule) {
-			if (!allowDeclarationsAfterNestedRules) {
-				ensureCorrectMixingOfNestingRulesAndDeclarations(rule)
-			}
 			walk(rule)
 		},
 	}
diff --git a/src/lib/mixing-nesting-rules-and-declarations.js b/src/lib/mixing-nesting-rules-and-declarations.js
deleted file mode 100644
index ba8c7f9..0000000
--- a/src/lib/mixing-nesting-rules-and-declarations.js
+++ /dev/null
@@ -1,41 +0,0 @@
-// see : https://www.w3.org/TR/css-nesting-1/#mixing
-export default function ensureCorrectMixingOfNestingRulesAndDeclarations(node) {
-	const hasNestedChildren = node.some((child) => {
-		return child.type === 'atrule' || child.type === 'rule'
-	})
-
-	if (!hasNestedChildren) {
-		return
-	}
-
-	// Clone with only declarations
-	const clone = node.cloneBefore()
-
-	let encounteredNestedRule = false
-	clone.each((child) => {
-		if (child.type === 'atrule' || child.type === 'rule') {
-			encounteredNestedRule = true
-			child.remove()
-			return
-		}
-
-		if (encounteredNestedRule) {
-			// declarations after nesting rules are not allowed
-			child.remove()
-			return
-		}
-	})
-
-	if (clone.nodes.length === 0) {
-		clone.remove()
-	}
-
-	// Remove all declarations and preserve nesting rules
-	node.each((child) => {
-		if (child.type === 'atrule' || child.type === 'rule') {
-			return
-		}
-
-		child.remove()
-	})
-}
diff --git a/test/basic.expect.css b/test/basic.expect.css
index 0536704..b3e0eb0 100644
--- a/test/basic.expect.css
+++ b/test/basic.expect.css
@@ -24,6 +24,12 @@ a {
 }
 	}
 
+a {
+
+	order: 5;
+	order: 6
+}
+
 a b {
 		order: 7;
 	}
@@ -37,6 +43,11 @@ a b {
 		order: 9;
 	}
 
+a {
+
+	order: 10
+}
+
 body a {
 		order: 11
 }
@@ -50,6 +61,11 @@ body a {
 		order: 13
 }
 
+a {
+
+	order: 14
+}
+
 @media screen {
 
 a {
diff --git a/test/direct.expect.css b/test/direct.expect.css
index 56919d6..7af20b4 100644
--- a/test/direct.expect.css
+++ b/test/direct.expect.css
@@ -10,6 +10,9 @@ a, b {
 :is(a,b) c, :is(a,b) d {
 		order: 4;
 	}
+a, b {
+	order: 5;
+}
 a, b {
 	order: 1;
 }
@@ -22,3 +25,6 @@ a, b {
 :is(a,b) c, :is(a,b) d {
 		order: 4;
 }
+a, b {
+	order: 5;
+}
diff --git a/test/empty.expect.css b/test/empty.expect.css
index 86e0b96..a23b4e2 100644
--- a/test/empty.expect.css
+++ b/test/empty.expect.css
@@ -11,6 +11,9 @@ d e {
 f g {
 		order: 4;
 	}
+f {
+	order: 5;
+}
 a b c {
 			order: 1
 }
@@ -23,3 +26,6 @@ d e {
 f g {
 		order: 4;
 }
+f {
+	order: 5;
+}
diff --git a/test/ignore.expect.css b/test/ignore.expect.css
index 2738441..13bdd8e 100644
--- a/test/ignore.expect.css
+++ b/test/ignore.expect.css
@@ -1,7 +1,5 @@
 a, b {
-	order: 1
-}
-a, b {
+	order: 1;
 	c, d {
 		order: 2;
 	}
@@ -13,9 +11,7 @@ f:is(g) {
 		order: 5;
 	}
 a, b {
-	order: 1
-}
-a, b {
+	order: 1;
 	@nest c, d {
 		order: 2;
 	}
diff --git a/test/mixin-declaration.css b/test/mixin-declaration.css
new file mode 100644
index 0000000..597a5ea
--- /dev/null
+++ b/test/mixin-declaration.css
@@ -0,0 +1,13 @@
+/* prevent regressions : https://github.com/csstools/postcss-nesting/issues/95 */
+body {
+	@mixin;
+
+	background: red;
+	font-size: 1rem;
+
+	@media (min-width: 64em) {
+		background: green;
+	}
+
+	margin: 0;
+}
diff --git a/test/mixin-declaration.expect.css b/test/mixin-declaration.expect.css
new file mode 100644
index 0000000..01a3db4
--- /dev/null
+++ b/test/mixin-declaration.expect.css
@@ -0,0 +1,15 @@
+/* prevent regressions : https://github.com/csstools/postcss-nesting/issues/95 */
+body {color: blue;
+
+	background: red;
+	font-size: 1rem;
+}
+@media (min-width: 64em) {
+body {
+		background: green;
+}
+	}
+body {
+
+	margin: 0;
+}
diff --git a/test/mixin.css b/test/mixin-rule.css
similarity index 100%
rename from test/mixin.css
rename to test/mixin-rule.css
diff --git a/test/mixin.expect.css b/test/mixin-rule.expect.css
similarity index 100%
rename from test/mixin.expect.css
rename to test/mixin-rule.expect.css
diff --git a/test/mixing-nested-rules-and-declarations-legacy.css b/test/mixing-nested-rules-and-declarations-legacy.css
deleted file mode 100644
index 6b88ed4..0000000
--- a/test/mixing-nested-rules-and-declarations-legacy.css
+++ /dev/null
@@ -1,19 +0,0 @@
-a {
-	order: 1;
-
-	& b {
-		order: 2;
-	}
-
-	order: 3;
-}
-
-a {
-	order: 4;
-
-	@nest b & {
-		order: 5;
-	}
-
-	order: 6;
-}
diff --git a/test/mixing-nested-rules-and-declarations-legacy.expect.css b/test/mixing-nested-rules-and-declarations-legacy.expect.css
deleted file mode 100644
index 00cba8f..0000000
--- a/test/mixing-nested-rules-and-declarations-legacy.expect.css
+++ /dev/null
@@ -1,25 +0,0 @@
-a {
-	order: 1;
-}
-
-a b {
-		order: 2;
-	}
-
-a {
-
-	order: 3;
-}
-
-a {
-	order: 4;
-}
-
-b a {
-		order: 5;
-}
-
-a {
-
-	order: 6;
-}
diff --git a/test/mixing-nested-rules-and-declarations-spec.css b/test/mixing-nested-rules-and-declarations-spec.css
deleted file mode 100644
index 6b88ed4..0000000
--- a/test/mixing-nested-rules-and-declarations-spec.css
+++ /dev/null
@@ -1,19 +0,0 @@
-a {
-	order: 1;
-
-	& b {
-		order: 2;
-	}
-
-	order: 3;
-}
-
-a {
-	order: 4;
-
-	@nest b & {
-		order: 5;
-	}
-
-	order: 6;
-}
diff --git a/test/mixing-nested-rules-and-declarations-spec.expect.css b/test/mixing-nested-rules-and-declarations-spec.expect.css
deleted file mode 100644
index d96af15..0000000
--- a/test/mixing-nested-rules-and-declarations-spec.expect.css
+++ /dev/null
@@ -1,15 +0,0 @@
-a {
-	order: 1;
-}
-
-a b {
-		order: 2;
-	}
-
-a {
-	order: 4;
-}
-
-b a {
-		order: 5;
-}
diff --git a/test/spec-examples.css b/test/spec-examples.css
index 15dc8ba..05bf802 100644
--- a/test/spec-examples.css
+++ b/test/spec-examples.css
@@ -377,6 +377,10 @@ article {
 		color: blue;
 	}
 
+	/*
+		NOTE : We are more forgiving than the spec
+		This declaration is preserved
+	*/
 	color: red;
 }
 
@@ -387,6 +391,10 @@ article {
 		color: blue;
 	}
 
+	/*
+		NOTE : We are more forgiving than the spec
+		This declaration is preserved
+	*/
 	color: red;
 
 	&.foo {
diff --git a/test/spec-examples.expect.css b/test/spec-examples.expect.css
index 8f26d2c..7a888ab 100644
--- a/test/spec-examples.expect.css
+++ b/test/spec-examples.expect.css
@@ -158,9 +158,7 @@ figure>figcaption>p {
 
 /* No & at all */
 .foo {
-	color: blue
-}
-.foo {
+	color: blue;
 
 	.bar {
 		color: red;
@@ -169,9 +167,7 @@ figure>figcaption>p {
 
 /* & isn’t the first simple selector */
 .foo {
-	color: blue
-}
-.foo {
+	color: blue;
 
 	.bar& {
 		color: red;
@@ -181,10 +177,7 @@ figure>figcaption>p {
 /* & isn’t the first selector of every one in the list */
 .foo,
 .bar {
-	color: blue
-}
-.foo,
-.bar {
+	color: blue;
 
 	&+.baz,
 	.qux {
@@ -232,10 +225,7 @@ figure>figcaption>p {
 */
 
 .foo {
-	color: red
-}
-
-.foo {
+	color: red;
 
 	@nest .bar {
 		color: blue;
@@ -245,10 +235,7 @@ figure>figcaption>p {
 /* Invalid because there’s no nesting selector */
 
 .foo {
-	color: red
-}
-
-.foo {
+	color: red;
 
 	@nest & .bar,
 	.baz {
@@ -357,10 +344,7 @@ figure>figcaption>p {
   contain a nesting selector */
 
 .foo {
-	color: red
-}
-
-.foo {
+	color: red;
 
 	@nest @media (min-width: 480px) {
 		& {
@@ -378,6 +362,12 @@ article {
 }
 article {
 		color: blue;
+
+	/*
+		NOTE : We are more forgiving than the spec
+		This declaration is preserved
+	*/
+	color: red;
 	}
 
 article {
@@ -386,8 +376,19 @@ article {
 
 article {
 		color: blue;
+
+	/*
+		NOTE : We are more forgiving than the spec
+		This declaration is preserved
+	*/
+	color: red;
 	}
 
 article.foo {
 		color: yellow;
 	}
+
+article {
+
+	/* valid! */
+	}