diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 8115371..a44b6f6 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -1,4 +1,4 @@
-*syntax.txt*	For Vim version 9.1.  Last change: 2025 Mar 10
+*syntax.txt*	For Vim version 9.1.  Last change: 2025 Mar 15
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -1286,6 +1286,21 @@
 startup vimrc: >
    :let filetype_w = "cweb"
 
+CSHARP							 *cs.vim* *ft-cs-syntax*
+
+C# raw string literals may use any number of quote marks to encapsulate the
+block, and raw interpolated string literals may use any number of braces to
+encapsulate the interpolation, e.g. >
+
+    $$$""""Hello {{{name}}}""""
+<
+By default, Vim highlights 3-8 quote marks, and 1-8 interpolation braces.
+The maximum numbers of quotes and braces recognized can configured using the
+following variables:
+
+    Variable					Default ~
+    g:cs_raw_string_quote_count			8
+    g:cs_raw_string_interpolation_brace_count	8
 
 DART						*dart.vim* *ft-dart-syntax*
 
diff --git a/runtime/doc/tags b/runtime/doc/tags
index 3bd49d9..c25effa 100644
--- a/runtime/doc/tags
+++ b/runtime/doc/tags
@@ -6722,6 +6722,7 @@
 credits	intro.txt	/*credits*
 crontab	options.txt	/*crontab*
 cs-find	if_cscop.txt	/*cs-find*
+cs.vim	syntax.txt	/*cs.vim*
 cs7-problem	term.txt	/*cs7-problem*
 cscope	if_cscop.txt	/*cscope*
 cscope-commands	if_cscop.txt	/*cscope-commands*
@@ -7319,6 +7320,7 @@
 ft-context-mappings	ft_context.txt	/*ft-context-mappings*
 ft-context-settings	ft_context.txt	/*ft-context-settings*
 ft-cpp-syntax	syntax.txt	/*ft-cpp-syntax*
+ft-cs-syntax	syntax.txt	/*ft-cs-syntax*
 ft-csh-syntax	syntax.txt	/*ft-csh-syntax*
 ft-css-omni	insert.txt	/*ft-css-omni*
 ft-csv-syntax	syntax.txt	/*ft-csv-syntax*
diff --git a/runtime/ftplugin/cs.vim b/runtime/ftplugin/cs.vim
index ada7131..d40fe43 100644
--- a/runtime/ftplugin/cs.vim
+++ b/runtime/ftplugin/cs.vim
@@ -2,8 +2,7 @@
 " Language:            C#
 " Maintainer:          Nick Jensen <nickspoon@gmail.com>
 " Former Maintainer:   Johannes Zellner <johannes@zellner.org>
-" Last Change:         2022-11-16
-"                      2024 Jan 14 by Vim Project (browsefilter)
+" Last Change:         2025-03-14
 " License:             Vim (see :h license)
 " Repository:          https://github.com/nickspoons/vim-cs
 
@@ -21,8 +20,11 @@
 
 " Set 'comments' to format dashed lists in comments.
 setlocal comments=sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,:///,://
+setlocal commentstring=//\ %s
 
-let b:undo_ftplugin = 'setl com< fo<'
+setlocal cinoptions=J1
+
+let b:undo_ftplugin = 'setl com< fo< cino<'
 
 if exists('loaded_matchit') && !exists('b:match_words')
   " #if/#endif support included by default
diff --git a/runtime/syntax/cs.vim b/runtime/syntax/cs.vim
index 104470a..3ae6bfc 100644
--- a/runtime/syntax/cs.vim
+++ b/runtime/syntax/cs.vim
@@ -3,7 +3,7 @@
 " Maintainer:          Nick Jensen <nickspoon@gmail.com>
 " Former Maintainers:  Anduin Withers <awithers@anduin.com>
 "                      Johannes Zellner <johannes@zellner.org>
-" Last Change:         2022-11-16
+" Last Change:         2025-03-14
 " Filenames:           *.cs
 " License:             Vim (see :h license)
 " Repository:          https://github.com/nickspoons/vim-cs
@@ -190,6 +190,18 @@
 syn match	csUnicodeSpecifier	+\\[uUx]+ contained display
 
 syn region	csString	matchgroup=csQuote start=+"+ end=+"\%(u8\)\=+ end=+$+ extend contains=csSpecialChar,csSpecialError,csUnicodeNumber,@Spell
+
+for s:i in range(3, get(g:, "cs_raw_string_quote_count", 8))
+  exe 'syn region csRawString'       .. s:i .. ' matchgroup=csQuote start=+\z("\{' .. s:i .. '}\)+ end=+\z1+ oneline nextgroup=csRawStringError' .. s:i
+  exe 'syn region csRawString'       .. s:i .. ' matchgroup=csQuote start=+\z("\{' .. s:i .. '}\)\s*$+ end=+^\s*\z1+ nextgroup=csRawStringError' .. s:i .. ' contains=csRawStringError' .. s:i
+  exe 'syn match  csRawStringError'  .. s:i .. ' /\%("\{'        .. s:i .. '}\)\@' .. s:i .. '<="\+/ contained'
+  exe 'syn match  csRawStringError'  .. s:i .. ' /\S.\{-}\s*"\{' .. s:i .. '}"\@!/ contained'
+
+  exe 'hi def link csRawString'      .. s:i .. ' csString'
+  exe 'hi def link csRawStringError' .. s:i .. ' Error'
+endfor
+unlet s:i
+
 syn match	csCharacter	"'[^']*'" contains=csSpecialChar,csSpecialCharError,csUnicodeNumber display
 syn match	csCharacter	"'\\''" contains=csSpecialChar display
 syn match	csCharacter	"'[^\\]'" display
@@ -217,11 +229,26 @@
 syn match	csInterpolationFormatDel	+:+ contained display
 
 syn region	csVerbatimString	matchgroup=csQuote start=+@"+ end=+"\%(u8\)\=+ skip=+""+ extend contains=csVerbatimQuote,@Spell
+
+" Interpolated raw string literals
+for s:i in range(1, get(g:, "cs_raw_string_interpolation_brace_count", 8))
+  exe 'syn region csInterpolatedRawString'       .. s:i .. ' matchgroup=csQuote start=+$\{' .. s:i .. '}\z("""\+\)+ end=+\z1+ extend contains=csInterpolation' .. s:i .. ',csInterpolationDelimiterError' .. s:i .. ',@Spell'
+  exe 'syn match  csInterpolationDelimiterError' .. s:i .. ' "}\{' .. s:i .. '}" contained'
+  exe 'syn match  csInterpolationDelimiterError' .. s:i .. ' "{\{' .. 2 * s:i .. ',}" contained'
+  exe 'syn match  csInterpolationDelimiterError' .. s:i .. ' "}\{' .. 2 * s:i .. ',}" contained'
+  exe 'syn region csInterpolation'               .. s:i .. ' matchgroup=csInterpolationDelimiter start=+\%({\{' .. s:i .. '}\)\@' .. s:i .. '<!{\{' .. s:i .. '}{\@!+ end=+}\@<!}\{' .. s:i .. '}\%(}\{' .. s:i .. '}\)\@!+' ..
+        \ ' keepend contained contains=@csAll,csBraced,csBracketed,csInterpolationAlign,csInterpolationFormat,csInterpolationDelimiterError' .. s:i
+
+  exe 'hi def link csInterpolationDelimiterError' .. s:i .. ' Error'
+  exe 'hi def link csInterpolatedRawString'       .. s:i .. ' csRawString'
+endfor
+unlet s:i
+
 syn match	csVerbatimQuote	+""+ contained
 
 syn region	csInterVerbString	matchgroup=csQuote start=+$@"+ start=+@$"+ end=+"\%(u8\)\=+ skip=+""+ extend contains=csInterpolation,csEscapedInterpolation,csSpecialChar,csSpecialError,csUnicodeNumber,csVerbatimQuote,@Spell
 
-syn cluster	csString	contains=csString,csInterpolatedString,csVerbatimString,csInterVerbString
+syn cluster	csString	contains=csString,csInterpolatedString,csVerbatimString,csInterVerbString,csRawString
 
 syn cluster	csLiteral	contains=csBoolean,@csNumber,csCharacter,@csString,csNull
 
@@ -282,6 +309,8 @@
 hi def link	csSpecialError	Error
 hi def link	csSpecialCharError	Error
 hi def link	csString	String
+hi def link	csRawString	csString
+hi def link	csRawStringError	Error
 hi def link	csQuote	String
 hi def link	csInterpolatedString	String
 hi def link	csVerbatimString	String