diff --git a/examples/custom_at_rule.rs b/examples/custom_at_rule.rs
index e4364bfa..3404a701 100644
--- a/examples/custom_at_rule.rs
+++ b/examples/custom_at_rule.rs
@@ -137,6 +137,7 @@ impl<'i> AtRuleParser<'i> for TailwindAtRuleParser {
     prelude: Self::Prelude,
     start: &ParserState,
     _options: &ParserOptions<'_, 'i>,
+    _is_nested: bool,
   ) -> Result<Self::AtRule, ()> {
     let loc = start.source_location();
     match prelude {
diff --git a/node/src/at_rule_parser.rs b/node/src/at_rule_parser.rs
index 3f85607a..111bd106 100644
--- a/node/src/at_rule_parser.rs
+++ b/node/src/at_rule_parser.rs
@@ -103,6 +103,7 @@ impl<'i> AtRuleParser<'i> for CustomAtRuleParser {
     start: &ParserState,
     input: &mut Parser<'i, 't>,
     options: &ParserOptions<'_, 'i>,
+    is_nested: bool,
   ) -> Result<Self::AtRule, ParseError<'i, Self::Error>> {
     let config = self.configs.get(prelude.name.as_ref()).unwrap();
     let body = if let Some(body) = &config.body {
@@ -114,7 +115,7 @@ impl<'i> AtRuleParser<'i> for CustomAtRuleParser {
           Some(AtRuleBody::RuleList(CssRuleList::parse_with(input, options, self)?))
         }
         CustomAtRuleBodyType::StyleBlock => Some(AtRuleBody::RuleList(CssRuleList::parse_style_block_with(
-          input, options, self,
+          input, options, self, is_nested,
         )?)),
       }
     } else {
@@ -139,6 +140,7 @@ impl<'i> AtRuleParser<'i> for CustomAtRuleParser {
     prelude: Self::Prelude,
     start: &ParserState,
     options: &ParserOptions<'_, 'i>,
+    _is_nested: bool,
   ) -> Result<Self::AtRule, ()> {
     let config = self.configs.get(prelude.name.as_ref()).unwrap();
     if config.body.is_some() {
diff --git a/node/test/customAtRules.mjs b/node/test/customAtRules.mjs
index e5cb00d3..d0c4ea58 100644
--- a/node/test/customAtRules.mjs
+++ b/node/test/customAtRules.mjs
@@ -59,12 +59,12 @@ test('mixin', () => {
     code: Buffer.from(`
       @mixin color {
         color: red;
-  
+
         &.bar {
           color: yellow;
         }
       }
-  
+
       .foo {
         @apply color;
       }
@@ -187,6 +187,30 @@ test('style block', () => {
   assert.equal(res.code.toString(), '@media (width<=1024px){.foo{color:#ff0}.foo.bar{color:red}}');
 });
 
+test('style block top level', () => {
+  let res = transform({
+    filename: 'test.css',
+    minify: true,
+    code: Buffer.from(`
+      @test {
+        .foo {
+          background: black;
+        }
+      }
+    `),
+    drafts: {
+      nesting: true
+    },
+    customAtRules: {
+      test: {
+        body: 'style-block'
+      }
+    }
+  });
+
+  assert.equal(res.code.toString(), '@test{.foo{background:#000}}');
+});
+
 test('multiple', () => {
   let res = transform({
     filename: 'test.css',
diff --git a/src/parser.rs b/src/parser.rs
index 91bc3d15..ec7e415b 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -643,7 +643,7 @@ impl<'a, 'o, 'b, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for Ne
         loc,
       })),
       AtRulePrelude::Custom(prelude) => {
-        parse_custom_at_rule_body(prelude, input, start, self.options, self.at_rule_parser)
+        parse_custom_at_rule_body(prelude, input, start, self.options, self.at_rule_parser, false)
       }
     }
   }
@@ -670,7 +670,7 @@ impl<'a, 'o, 'b, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for Ne
         loc,
       })),
       AtRulePrelude::Custom(prelude) => {
-        parse_custom_at_rule_without_block(prelude, start, self.options, self.at_rule_parser)
+        parse_custom_at_rule_without_block(prelude, start, self.options, self.at_rule_parser, false)
       }
       _ => Err(()),
     }
@@ -703,7 +703,7 @@ impl<'a, 'o, 'b, 'i, T: crate::traits::AtRuleParser<'i>> QualifiedRuleParser<'i>
   ) -> Result<CssRule<'i, T::AtRule>, ParseError<'i, Self::Error>> {
     let loc = self.loc(start);
     let (declarations, rules) = if self.options.flags.contains(ParserFlags::NESTING) {
-      parse_declarations_and_nested_rules(input, self.options, self.at_rule_parser)?
+      parse_declarations_and_nested_rules(input, self.options, self.at_rule_parser, true)?
     } else {
       (DeclarationBlock::parse(input, self.options)?, CssRuleList(vec![]))
     };
@@ -752,9 +752,10 @@ fn parse_custom_at_rule_body<'i, 't, T: crate::traits::AtRuleParser<'i>>(
   start: &ParserState,
   options: &ParserOptions<'_, 'i>,
   at_rule_parser: &mut T,
+  is_nested: bool,
 ) -> Result<CssRule<'i, T::AtRule>, ParseError<'i, ParserError<'i>>> {
   at_rule_parser
-    .parse_block(prelude, start, input, options)
+    .parse_block(prelude, start, input, options, is_nested)
     .map(|prelude| CssRule::Custom(prelude))
     .map_err(|err| match &err.kind {
       ParseErrorKind::Basic(kind) => ParseError {
@@ -770,9 +771,10 @@ fn parse_custom_at_rule_without_block<'i, 't, T: crate::traits::AtRuleParser<'i>
   start: &ParserState,
   options: &ParserOptions<'_, 'i>,
   at_rule_parser: &mut T,
+  is_nested: bool,
 ) -> Result<CssRule<'i, T::AtRule>, ()> {
   at_rule_parser
-    .rule_without_block(prelude, start, options)
+    .rule_without_block(prelude, start, options, is_nested)
     .map(|prelude| CssRule::Custom(prelude))
 }
 
@@ -780,6 +782,7 @@ fn parse_declarations_and_nested_rules<'a, 'o, 'i, 't, T: crate::traits::AtRuleP
   input: &mut Parser<'i, 't>,
   options: &'a ParserOptions<'o, 'i>,
   at_rule_parser: &mut T,
+  is_nested: bool,
 ) -> Result<(DeclarationBlock<'i>, CssRuleList<'i, T::AtRule>), ParseError<'i, ParserError<'i>>> {
   let mut important_declarations = DeclarationList::new();
   let mut declarations = DeclarationList::new();
@@ -790,6 +793,7 @@ fn parse_declarations_and_nested_rules<'a, 'o, 'i, 't, T: crate::traits::AtRuleP
     important_declarations: &mut important_declarations,
     rules: &mut rules,
     at_rule_parser,
+    is_nested,
   };
 
   // In the v2 nesting spec, declarations and nested rules may be mixed.
@@ -840,6 +844,7 @@ pub struct StyleRuleParser<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> {
   important_declarations: &'a mut DeclarationList<'i>,
   rules: &'a mut CssRuleList<'i, T::AtRule>,
   at_rule_parser: &'a mut T,
+  is_nested: bool,
 }
 
 /// Parse a declaration within {} block: `color: blue`
@@ -925,7 +930,7 @@ impl<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for StyleR
       AtRulePrelude::Media(query) => {
         self.rules.0.push(CssRule::Media(MediaRule {
           query,
-          rules: parse_nested_at_rule(input, self.options, self.at_rule_parser)?,
+          rules: parse_style_block(input, self.options, self.at_rule_parser, true)?,
           loc,
         }));
         Ok(())
@@ -933,7 +938,7 @@ impl<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for StyleR
       AtRulePrelude::Supports(condition) => {
         self.rules.0.push(CssRule::Supports(SupportsRule {
           condition,
-          rules: parse_nested_at_rule(input, self.options, self.at_rule_parser)?,
+          rules: parse_style_block(input, self.options, self.at_rule_parser, true)?,
           loc,
         }));
         Ok(())
@@ -942,7 +947,7 @@ impl<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for StyleR
         self.rules.0.push(CssRule::Container(ContainerRule {
           name,
           condition,
-          rules: parse_nested_at_rule(input, self.options, self.at_rule_parser)?,
+          rules: parse_style_block(input, self.options, self.at_rule_parser, true)?,
           loc,
         }));
         Ok(())
@@ -950,20 +955,21 @@ impl<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for StyleR
       AtRulePrelude::LayerBlock(name) => {
         self.rules.0.push(CssRule::LayerBlock(LayerBlockRule {
           name,
-          rules: parse_nested_at_rule(input, self.options, self.at_rule_parser)?,
+          rules: parse_style_block(input, self.options, self.at_rule_parser, true)?,
           loc,
         }));
         Ok(())
       }
       AtRulePrelude::StartingStyle => {
         self.rules.0.push(CssRule::StartingStyle(StartingStyleRule {
-          rules: parse_nested_at_rule(input, self.options, self.at_rule_parser)?,
+          rules: parse_style_block(input, self.options, self.at_rule_parser, true)?,
           loc,
         }));
         Ok(())
       }
       AtRulePrelude::Nest(selectors) => {
-        let (declarations, rules) = parse_declarations_and_nested_rules(input, self.options, self.at_rule_parser)?;
+        let (declarations, rules) =
+          parse_declarations_and_nested_rules(input, self.options, self.at_rule_parser, true)?;
         self.rules.0.push(CssRule::Nesting(NestingRule {
           style: StyleRule {
             selectors,
@@ -992,6 +998,7 @@ impl<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for StyleR
           start,
           self.options,
           self.at_rule_parser,
+          true,
         )?);
         Ok(())
       }
@@ -1021,6 +1028,7 @@ impl<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for StyleR
           start,
           self.options,
           self.at_rule_parser,
+          true,
         )?);
         Ok(())
       }
@@ -1029,10 +1037,11 @@ impl<'a, 'o, 'i, T: crate::traits::AtRuleParser<'i>> AtRuleParser<'i> for StyleR
   }
 }
 
-pub fn parse_nested_at_rule<'a, 'o, 'i, 't, T: crate::traits::AtRuleParser<'i>>(
+pub fn parse_style_block<'a, 'o, 'i, 't, T: crate::traits::AtRuleParser<'i>>(
   input: &mut Parser<'i, 't>,
   options: &'a ParserOptions<'o, 'i>,
   at_rule_parser: &mut T,
+  is_nested: bool,
 ) -> Result<CssRuleList<'i, T::AtRule>, ParseError<'i, ParserError<'i>>> {
   let loc = input.current_source_location();
   let loc = Location {
@@ -1043,7 +1052,7 @@ pub fn parse_nested_at_rule<'a, 'o, 'i, 't, T: crate::traits::AtRuleParser<'i>>(
 
   // Declarations can be immediately within @media and @supports blocks that are nested within a parent style rule.
   // These act the same way as if they were nested within a `& { ... }` block.
-  let (declarations, mut rules) = parse_declarations_and_nested_rules(input, options, at_rule_parser)?;
+  let (declarations, mut rules) = parse_declarations_and_nested_rules(input, options, at_rule_parser, is_nested)?;
 
   if declarations.len() > 0 {
     rules.0.insert(
@@ -1073,10 +1082,14 @@ impl<'a, 'o, 'b, 'i, T: crate::traits::AtRuleParser<'i>> QualifiedRuleParser<'i>
     input: &mut Parser<'i, 't>,
   ) -> Result<Self::Prelude, ParseError<'i, Self::Error>> {
     let selector_parser = SelectorParser {
-      is_nesting_allowed: true,
+      is_nesting_allowed: self.options.flags.contains(ParserFlags::NESTING),
       options: &self.options,
     };
-    SelectorList::parse_relative(&selector_parser, input, NestingRequirement::Implicit)
+    if self.is_nested {
+      SelectorList::parse_relative(&selector_parser, input, NestingRequirement::Implicit)
+    } else {
+      SelectorList::parse(&selector_parser, input, NestingRequirement::None)
+    }
   }
 
   fn parse_block<'t>(
@@ -1086,7 +1099,8 @@ impl<'a, 'o, 'b, 'i, T: crate::traits::AtRuleParser<'i>> QualifiedRuleParser<'i>
     input: &mut Parser<'i, 't>,
   ) -> Result<(), ParseError<'i, Self::Error>> {
     let loc = start.source_location();
-    let (declarations, rules) = parse_declarations_and_nested_rules(input, self.options, self.at_rule_parser)?;
+    let (declarations, rules) =
+      parse_declarations_and_nested_rules(input, self.options, self.at_rule_parser, true)?;
     self.rules.0.push(CssRule::Style(StyleRule {
       selectors,
       vendor_prefix: VendorPrefix::empty(),
diff --git a/src/rules/mod.rs b/src/rules/mod.rs
index 92e54006..f13f69e0 100644
--- a/src/rules/mod.rs
+++ b/src/rules/mod.rs
@@ -63,9 +63,7 @@ use crate::context::PropertyHandlerContext;
 use crate::declaration::{DeclarationBlock, DeclarationHandler};
 use crate::dependencies::{Dependency, ImportDependency};
 use crate::error::{MinifyError, ParserError, PrinterError, PrinterErrorKind};
-use crate::parser::{
-  parse_nested_at_rule, DefaultAtRule, DefaultAtRuleParser, NestedRuleParser, TopLevelRuleParser,
-};
+use crate::parser::{parse_style_block, DefaultAtRule, DefaultAtRuleParser, NestedRuleParser, TopLevelRuleParser};
 use crate::prefixes::Feature;
 use crate::printer::Printer;
 use crate::rules::keyframes::KeyframesName;
@@ -422,8 +420,9 @@ impl<'i> CssRuleList<'i, DefaultAtRule> {
   pub fn parse_style_block<'t>(
     input: &mut Parser<'i, 't>,
     options: &ParserOptions<'_, 'i>,
+    is_nested: bool,
   ) -> Result<Self, ParseError<'i, ParserError<'i>>> {
-    Self::parse_style_block_with(input, options, &mut DefaultAtRuleParser)
+    Self::parse_style_block_with(input, options, &mut DefaultAtRuleParser, is_nested)
   }
 }
 
@@ -447,8 +446,9 @@ impl<'i, T> CssRuleList<'i, T> {
     input: &mut Parser<'i, 't>,
     options: &ParserOptions<'_, 'i>,
     at_rule_parser: &mut P,
+    is_nested: bool,
   ) -> Result<Self, ParseError<'i, ParserError<'i>>> {
-    parse_nested_at_rule(input, options, at_rule_parser)
+    parse_style_block(input, options, at_rule_parser, is_nested)
   }
 }
 
diff --git a/src/traits.rs b/src/traits.rs
index 5237e016..81f62760 100644
--- a/src/traits.rs
+++ b/src/traits.rs
@@ -306,6 +306,7 @@ pub trait AtRuleParser<'i>: Sized {
   /// representation of the at-rule.
   ///
   /// The location passed in is source location of the start of the prelude.
+  /// `is_nested` indicates whether the rule is nested inside a style rule.
   ///
   /// This is only called when either the `;` semicolon indeed follows the prelude,
   /// or parser is at the end of the input.
@@ -314,16 +315,19 @@ pub trait AtRuleParser<'i>: Sized {
     prelude: Self::Prelude,
     start: &ParserState,
     options: &ParserOptions<'_, 'i>,
+    is_nested: bool,
   ) -> Result<Self::AtRule, ()> {
     let _ = prelude;
     let _ = start;
     let _ = options;
+    let _ = is_nested;
     Err(())
   }
 
   /// Parse the content of a `{ /* ... */ }` block for the body of the at-rule.
   ///
   /// The location passed in is source location of the start of the prelude.
+  /// `is_nested` indicates whether the rule is nested inside a style rule.
   ///
   /// Return the finished representation of the at-rule
   /// as returned by `RuleListParser::next` or `DeclarationListParser::next`,
@@ -336,11 +340,13 @@ pub trait AtRuleParser<'i>: Sized {
     start: &ParserState,
     input: &mut Parser<'i, 't>,
     options: &ParserOptions<'_, 'i>,
+    is_nested: bool,
   ) -> Result<Self::AtRule, ParseError<'i, Self::Error>> {
     let _ = prelude;
     let _ = start;
     let _ = input;
     let _ = options;
+    let _ = is_nested;
     Err(input.new_error(BasicParseErrorKind::AtRuleBodyInvalid))
   }
 }
diff --git a/tests/test_custom_parser.rs b/tests/test_custom_parser.rs
index b75fa9be..8e360ef2 100644
--- a/tests/test_custom_parser.rs
+++ b/tests/test_custom_parser.rs
@@ -101,6 +101,7 @@ impl<'i> AtRuleParser<'i> for TestAtRuleParser {
     prelude: Self::Prelude,
     _start: &ParserState,
     _options: &ParserOptions<'_, 'i>,
+    _is_nested: bool,
   ) -> Result<Self::AtRule, ()> {
     match prelude {
       Prelude::Inline(name) => Ok(AtRule::Inline(InlineRule { name })),
@@ -114,6 +115,7 @@ impl<'i> AtRuleParser<'i> for TestAtRuleParser {
     _start: &ParserState,
     input: &mut Parser<'i, 't>,
     _options: &ParserOptions<'_, 'i>,
+    _is_nested: bool,
   ) -> Result<Self::AtRule, ParseError<'i, Self::Error>> {
     match prelude {
       Prelude::Block(name) => Ok(AtRule::Block(BlockRule {