@precedence {
  attribute @left,
  structure @left,
  call,
  valueCompareOp,
  valueOp @left,
  layerName
}

@skip { whitespace | Comment }

@top StyleSheet { item* }

@top Styles { blockContent }

item {
  RuleSet |
  ImportStatement |
  MediaStatement |
  CharsetStatement |
  NamespaceStatement |
  KeyframesStatement |
  SupportsStatement |
  ScopeStatement |
  AtRule
}

RuleSet {
  selector ("," selector)* Block
}

ImportStatement {
  atKw<"import">
  value
  Layer {
    queryCalleeKw<"layer"> (!layerName "(" LayerName ("." LayerName)* ")")? |
    queryKw<"layer">
  }?
  commaSep<query> ";"
}

LayerName { identifier }

MediaStatement {
  atKw<"media"> commaSep<query> Block
}

CharsetStatement {
  atKw<"charset"> value ";"
}

NamespaceStatement {
  atKw<"namespace">
  NamespaceName { identifier }?
  (StringLiteral | CallLiteral) ";"
}

KeyframesStatement {
  atKw<"keyframes">
  KeyframeName { identifier | StringLiteral }
  KeyframeList
}

KeyframeSelector {
  KeyframeRangeName { identifier } NumberLiteral? |
  NumberLiteral
}

KeyframeList {
  "{" (KeyframeSelector ("," KeyframeSelector)* Block)* "}"
}

SupportsStatement {
  atKw<"supports"> query Block
}

ScopeStatement {
  atKw<"scope">
  ParenthesizedSelector?
  (@extend[@name=to]<identifier, "to"> ParenthesizedSelector)?
  Block
}

AtRule { AtKeyword commaSep<query> (";" | Block) }

Block[@dynamicPrecedence=1] { "{" blockContent "}" }

blockContent { ~item item* (Declaration (";" ~item item* Declaration?)*)? }

selector {
  UniversalSelector |
  TagSelector { ~item TagName { identifier ~item } } |
  NestingSelector |
  ClassSelector { selector? !attribute "." ClassName { identifier } } |
  PseudoClassSelector {
    selector? !attribute (":" | "::") (
      PseudoClassName { identifier } |
      pseudoClassWithArg ArgList<value+> |
      PseudoClassName { callee } ArgList<selector>)
  } |
  IdSelector { selector? !attribute "#" IdName { identifier } } |
  AttributeSelector { selector? !attribute "[" AttributeName { identifier } (MatchOp value)? "]" } |
  ChildSelector { selector? !structure ChildOp selector } |
  DescendantSelector { selector !structure descendantOp selector } |
  SiblingSelector { selector? !structure SiblingOp selector }
}

pseudoClassWithArg {
  @specialize[@name=PseudoClassName]<callee, "lang" | "nth-child" | "nth-last-child" | "nth-of-type" | "nth-last-of-type" | "nth-of-type" | "dir" | "host-context">
}

NumberLiteral {
  numberLiteralInner Unit?
}

ArgList<content> { "(" commaSep<content> ")" }

Declaration {
  (PropertyName { identifier ~item } | VariableName)
  ":" (value (","? value)*)? Important?
}

query {
  KeywordQuery { queryIdentifier } |
  FeatureQuery { "(" FeatureName ":" value+ ")" } |
  BinaryQuery { query !valueOp @specialize[@name=LogicOp]<queryIdentifier, "or" | "and"> query } |
  ComparisonQuery {
    "("
    (queryValue | FeatureName) !valueCompareOp CompareOp (queryValue | FeatureName)
    (!valueCompareOp CompareOp (queryValue | FeatureName))?
    ")"
  } |
  UnaryQuery { @specialize[@name=UnaryQueryOp]<queryIdentifier, "not" | "only"> query } |
  ParenthesizedQuery { "(" query ")" } |
  SelectorQuery { queryCalleeKw<"selector"> ParenthesizedSelector } |
  CallQuery { QueryCallee ArgList<FeatureName ":" value+ | query> }
}

ParenthesizedSelector { "(" selector ")" }

FeatureName { queryIdentifier }

value {
  VariableName |
  ValueName { identifier } |
  ParenthesizedValue { "(" token* ")" } |
  BracketedValue { "[" token* "]" } |
  BracedValue { "{" token* "}" } |
  ColorLiteral |
  NumberLiteral |
  StringLiteral |
  BinaryExpression { value !valueOp BinOp value } |
  CallExpression |
  IfExpression |
  CallLiteral
}

token {
  value |
  AtKeyword |
  "#" | ";" | "." | ":"    
}

queryValue {
  queryVariableName |
  ColorLiteral |
  NumberLiteral |
  StringLiteral
}

IfExpression {
  @specialize[@name=if]<callee, "if"> ArgList {
    "(" (IfBranch ";")* IfBranch ";"? ")"
  }
}

IfBranch { query ":" value }

CallLiteral {
  @specialize[@name=CallTag]<callee, "url" | "url-prefix" | "domain" | "regexp">
  "(" (ParenthesizedContent | StringLiteral)? ")"
}

CallExpression {
  (Callee { callee } | VariableName) !call ArgList<value+>
}

@skip {} {
  Comment[isolate] { "/*" (commentContent | commentLineBreak)* commentEnd }
}

@local tokens {
  commentEnd { "*/" | @eof }
  commentLineBreak { "\n" }
  @else commentContent
}

commaSep<value> { "" | value ("," value?)* }

queryKw<name> { @specialize[@name={name}]<queryIdentifier, name> }
queryCalleeKw<name> { @specialize[@name={name}]<QueryCallee, name> }

atKw<name> { @specialize[@name={name}]<AtKeyword, "@" name> }

@external tokens descendant from "./tokens" {
  descendantOp
}

@external tokens unitToken from "./tokens" {
  Unit
}

@external tokens identifiers from "./tokens" {
  identifier,
  callee,
  VariableName
}

@external tokens queryIdentifiers from "./tokens" {
  @conflict { identifier, VariableName, callee }
  queryIdentifier,
  queryVariableName[@name=VariableName],
  QueryCallee
}

@tokens {
  UniversalSelector { "*" }

  NestingSelector { "&" }

  AtKeyword { "@" "-"? @asciiLetter (@asciiLetter | @digit | "-")* }

  MatchOp { $[~^|*$]? "=" }

  ChildOp { ">" ">"? }

  CompareOp { $[<>] "="? | "=" }

  SiblingOp { "~" | "+" }

  BinOp { $[+\-*/] }

  Important { "!important" }

  whitespace { @whitespace+ }

  hexDigit { @digit | $[a-fA-F] }

  ParenthesizedContent { !['")] ![)]+ }

  @precedence { whitespace, ParenthesizedContent, "/*" }

  ColorLiteral {
    "#" hexDigit hexDigit hexDigit (hexDigit (hexDigit hexDigit (hexDigit hexDigit)?)?)?
  }

  numberLiteralInner { ("+" | "-")? (@digit+ ("." @digit*)? | "." @digit+) (("e" | "E") ("+" | "-")? @digit+)? }

  @precedence { numberLiteralInner, BinOp, SiblingOp }

  @precedence { numberLiteralInner, "." }

  StringLiteral[isolate] { "\"" (!["\n\\] | "\\" _)* "\"" | "'" (!['\n\\] | "\\" _)* "'" }

  "#" "."

  ":" "::" ";" ","

  "(" ")" "[" "]" "{" "}"
}

@external propSource cssHighlighting from "./highlight"

@detectDelim