Remove embedded_rules, add cascade layers

Since all browser support embedded rules now, lets just go ahead and
make that the standard

Author: amadeus

after/syntax/javascript.vim

@@ -17,9 +17,7 @@ endif
 "   unlet b:current_syntax
 " endif
 
-let b:embedded_rules = 1
 runtime! syntax/css.vim
-unlet b:embedded_rules
 
 syntax match jsStyledKeyword /\<styled\>/ skipwhite skipempty nextgroup=jsStyledDot,jsStyledParens
 " NOTE: This specific re-definition of jsFuncCall is to overwrite the current one

after/syntax/typescript.vim

@@ -17,9 +17,7 @@ endif
 "   unlet b:current_syntax
 " endif
 
-let b:embedded_rules = 1
 runtime! syntax/css.vim
-unlet b:embedded_rules
 
 syntax match tsStyledKeyword /\<styled\>/ skipwhite skipempty nextgroup=tsStyledDot,tsStyledParens
 " NOTE: This specific re-definition of tsFuncCall is to overwrite the current one

syntax/css.vim

@@ -11,10 +11,6 @@ if exists('b:current_syntax') && b:current_syntax ==# 'css'
   finish
 endif
 
-if !exists('b:embedded_rules') && main_syntax !=# 'css'
-  syntax clear
-endif
-
 let s:cpo_save = &cpoptions
 set cpoptions&vim
 
@@ -32,7 +28,8 @@ syntax match cssBracketError /}\|]/ containedin=ALLBUT,cssComment,cssGridNamedCo
 syntax match cssBrowserPrefix contained /\%(-webkit-\|-moz-\|-ms-\|-o-\)/ nextgroup=cssProp
 syntax match cssValueNoise contained /,/
 
-syntax match cssAtRule /@\(media\|page\|import\|charset\|namespace\)/ skipwhite skipempty nextgroup=cssAtRuleString
+syntax match cssAtRule /@\(media\|\|page\|import\|charset\|namespace\)/ skipwhite skipempty nextgroup=cssAtRuleString
+
 syntax region cssAtRuleString contained start=/"/ skip=/\\\\\|\\"/ end=/"/ contained skipwhite skipempty oneline nextgroup=cssAtRuleNoise
 syntax region cssAtRuleString contained start=/'/ skip=/\\\\\|\\'/ end=/'/ contained skipwhite skipempty oneline nextgroup=cssAtRuleNoise
 syntax match cssAtRuleNoise /;/ contained
@@ -52,7 +49,7 @@ syntax match cssClassSelectorDot /\./ contained
 syntax match cssClassSelectorEscapeChar /\\/ contained
 
 syntax match cssPseudoSelector /:\{1,2\}/ nextgroup=cssPseudoKeyword,cssPseudoFunction,cssPseudoFunctionType
-syntax match cssPseudoKeyword contained /\<active\|after\|before\|checked\|disabled\|empty\|first-child\|first-letter\|first-line\|first-of-type\|focus-within\|focus\|hover\|input-placeholder\|last-child\|last-line\|last-of-type\|left\|link\|only-child\|only-of-type\|placeholder\|right\|selection\|visited\|scrollbar-track-piece\|scrollbar-button\|scrollbar-corner\|scrollbar\>/ nextgroup=@cssSelectors,cssDefinitionBlock skipwhite skipempty
+syntax match cssPseudoKeyword contained /\<active\|after\|before\|checked\|disabled\|empty\|first-child\|first-letter\|first-line\|first-of-type\|focus-within\|focus\|hover\|input-placeholder\|last-child\|last-line\|last-of-type\|left\|link\|only-child\|only-of-type\|placeholder\|right\|selection\|visited\|scrollbar-track-piece\|scrollbar-button\|scrollbar-corner\|scrollbar\|root\>/ nextgroup=@cssSelectors,cssDefinitionBlock skipwhite skipempty
 
 syntax region cssPseudoFunction     contained start=/[a-zA-Z0-9-_]\+(/ end=/)/ keepend extend nextgroup=@cssSelectors,cssDefinitionBlock skipwhite skipempty contains=cssPseudoFunctionNot,cssPseudoFunctionDir,cssPseudoFunctionLang,cssPseudoFunctionType
 syntax region cssPseudoFunctionNot  contained matchgroup=cssFunctionDelimiters start=/not(/ end=/)/ contains=@cssSelectors
@@ -67,11 +64,7 @@ syntax match   cssPseudoFunctionTypeOperators contained /\%(+\|-\|n\)/
 
 syntax match cssPseudoKeyword contained /\%(-webkit-\|-moz-\|-ms-\|-o-\)\%(input-placeholder\|search-cancel-button\|search-decoration\|focus-inner\|resizer\|placeholder\|inner-spin-button\|outer-spin-button\|expand\|scrollbar-track-piece\|scrollbar-track\|scrollbar-thumb\|scrollbar-button\|scrollbar-corner\|scrollbar\|full-screen\|media-controls-enclosure\|file-upload-button\)/ contains=cssBrowserPrefix nextgroup=@cssSelectors,cssDefinitionBlock skipwhite skipempty
 
-if exists('b:embedded_rules')
-  syntax region cssDefinitionBlock contained matchgroup=cssDefinitionBraces start=/{/ end=/}/ extend contains=cssPropDefinition,@cssSelectors,cssMediaDefinition keepend extend fold
-else
-  syntax region cssDefinitionBlock matchgroup=cssDefinitionBraces start=/{/ end=/}/ extend contains=cssPropDefinition keepend fold
-endif
+syntax region cssDefinitionBlock contained matchgroup=cssDefinitionBraces start=/{/ end=/}/ extend contains=cssPropDefinition,@cssSelectors,cssMediaDefinition keepend extend fold
 
 syntax region cssAttributeSelector matchgroup=cssAttributeSelectorBraces start=/\[/ end=/\]/ nextgroup=@cssSelectors,cssDefinitionBlock skipwhite skipempty
 if exists('b:current_syntax')
@@ -218,6 +211,10 @@ syntax region cssCalcPrens contained start=/(/ end=/)/ matchgroup=cssFuncDelimit
 syntax region cssGridNamedColumns matchgroup=cssGridNamedColumnBrackets contained start=/\[/ end=/\]/  contains=cssColumnName extend keepend
 syntax match cssColumnName contained /\<[a-zA-Z0-9-]\+\>/ extend
 
+syntax match cssLayerComma contained /,/ skipwhite skipempty nextgroup=cssLayerName
+syntax match cssLayerName  contained /\k\+/ skipwhite skipempty nextgroup=cssAttrTypes,cssLayerComma,cssAtRuleNoise,cssDefinitionBlock
+syntax match cssLayer /@layer/ skipwhite skipempty nextgroup=cssLayerName,cssLayerComma,cssDefinitionBlock
+
 " syntax region cssFunction        contained start=/\<[a-zA-Z0-9-]\+\>\+(/ end=/)/ contains=cssFuncName keepend
 syntax match cssFuncName         /\<[a-zA-Z0-9-]\+\>(\@=/ nextgroup=cssFuncArgs,cssFuncUrlArgs,cssFuncVar,cssFuncAttrArgs,cssFuncEffectArgs,cssFuncCalcArgs
 syntax region cssFuncArgs        contained matchgroup=cssFuncDelimiters start=/(/ end=/)/ contains=cssFunction,cssString,cssNumber,cssHexColor,cssColor,cssOperators,cssValueNoise,cssFuncCalcArgs,cssFuncName,cssSafeAreaInsets,cssFuncArgs extend keepend
@@ -234,7 +231,7 @@ syntax match  cssAttrTypes    contained /\%(string\|integer\|color\|url\|integer
 syntax match  cssAttrComma    contained /,/ skipwhite skipempty nextgroup=cssString,cssNumber
 syntax match  cssOperators    contained /\%(+\|-\|*\|\/\)/
 
-syntax cluster cssSelectors contains=cssTagSelector,cssIDSelector,cssSelectorOperator,cssSelectorSeparator,cssStarSelector,cssClassSelector,cssPseudoSelector,cssAttributeSelector,cssPseudoFunction
+syntax cluster cssSelectors contains=cssTagSelector,cssIDSelector,cssSelectorOperator,cssSelectorSeparator,cssStarSelector,cssClassSelector,cssPseudoSelector,cssAttributeSelector,cssPseudoFunction,cssPseudoSelector
 syntax cluster cssRules contains=cssPropDefinition
 syntax cluster cssValues contains=cssFunction,cssString,cssNumber,cssHexColor,cssImportant,cssColor,cssValueKeyword,cssValueNoise,cssFuncName,cssGridNamedColumns
 
@@ -259,13 +256,15 @@ highlight default link cssAtRulePage                  PreProc
 highlight default link cssKeyframesDefinition         PreProc
 highlight default link cssFontFaceDefinition          PreProc
 highlight default link cssAtRule                      PreProc
+highlight default link cssLayer                       PreProc
 highlight default link cssBrowserPrefix               Comment
 highlight default link cssNumber                      Number
 highlight default link cssHexColor                    Number
 highlight default link cssTagSelector                 Statement
 highlight default link cssPseudoKeyword               Special
 highlight default link cssPagePseudos                 Special
 highlight default link cssValueKeyword                Constant
+highlight default link cssLayerName                   Constant
 highlight default link cssColor                       Constant
 highlight default link cssUnits                       Operator
 highlight default link cssNumberNoise                 Number
@@ -281,6 +280,7 @@ highlight default link cssFontBlock                   Constant
 highlight default link cssFontOperator                Operator
 highlight default link cssValueNoise                  Noise
 highlight default link cssKeyframeComma               Noise
+highlight default link cssLayerComma                  Noise
 highlight default link cssAnimationBlock              Constant
 highlight default link cssPageDefinition              Constant
 highlight default link cssKeyframe                    Constant

syntax/module.vim

@@ -14,9 +14,7 @@ endif
 syntax clear
 syntax match  cssmVariable           /\<[_a-zA-Z$]\+[_a-zA-Z0-9-]*\>/ containedin=cssValueBlock,cssTransitionBlock
 
-let b:embedded_rules = 1
 runtime! syntax/css.vim
-unlet b:embedded_rules
 
 syntax region cssmImport matchgroup=cssmImportKeywords start=/import/ end=/from/ contains=cssmClass skipwhite skipempty nextgroup=cssString
 syntax match cssmNoise /;/

syntax/scss.vim

@@ -11,9 +11,7 @@ if exists("b:current_syntax") && b:current_syntax == "scss"
   finish
 endif
 
-let b:embedded_rules = 1
 runtime! syntax/css.vim
-unlet b:embedded_rules
 
 syntax match  scssAmpersand containedin=cssDefinitionBlock /&/ nextgroup=@cssSelectors,cssDefinitionBlock skipwhite skipempty
 syntax match  scssComment /\/\/.*/ contains=@Spell containedin=cssDefinitionBlock

syntax/stylus.vim

@@ -14,9 +14,7 @@ endif
 syntax clear
 syntax match  stylusVariable           /\<[_a-zA-Z$]\+[_a-zA-Z0-9-]*\>/ containedin=cssValueBlock,cssTransitionBlock
 
-let b:embedded_rules = 1
 runtime! syntax/css.vim
-unlet b:embedded_rules
 
 setlocal iskeyword+=$