Fix broken Chroma CSS styles (#23174)

The CSS styles in Gitea themes are out-of-sync of Chroma's styles.

This PR introduces a `chroma-style-diff.go` tool to compare the diff.
The missing CSS styles have been added manually. They are left as empty
to reduce arguments because there was no color for them before.

And this PR fixes #22348, with just 2 lines changed: `.chroma .kt & .n`,
these colors are taken from GitHub.

It's good enough for #22348


![image](https://user-images.githubusercontent.com/2114189/221551941-0d27d11d-e71e-498f-8e88-92b558fe4a18.png)

---------

Co-authored-by: silverwind <me@silverwind.io>

.stylelintrc.yaml

@@ -1,12 +1,18 @@
 plugins:
   - stylelint-declaration-strict-value
 
+ignoreFiles:
+  - "**/*.go"
+
 overrides:
   - files: ["**/*.less"]
     customSyntax: postcss-less
   - files: ["**/chroma/*", "**/codemirror/*", "**/standalone/*", "**/console/*"]
     rules:
       scale-unlimited/declaration-strict-value: null
+  - files: ["**/chroma/*", "**/codemirror/*"]
+    rules:
+      block-no-empty: null
 
 rules:
   alpha-value-notation: null

web_src/less/chroma/chroma-style-diff.go

@@ -0,0 +1,79 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+//go:build ignore
+
+/*
+This tool is used to compare the CSS names in a chroma builtin styles with the Gitea theme CSS names.
+
+It outputs the difference between the two sets of CSS names, eg:
+
+```
+CSS names not in builtin:
+.chroma .ln
+----
+Builtin CSS names not in file:
+.chroma .vm
+```
+
+Developers could use this tool to re-sync the CSS names in the Gitea theme.
+*/
+
+package main
+
+import (
+	"os"
+	"regexp"
+	"strings"
+
+	"github.com/alecthomas/chroma/v2"
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		println("Usage: chroma-style-diff css-or-less-file")
+		os.Exit(1)
+	}
+
+	data, err := os.ReadFile(os.Args[1])
+	if err != nil {
+		println(err.Error())
+		os.Exit(1)
+	}
+
+	content := string(data)
+
+	// a simple CSS parser to collect CSS names
+	content = regexp.MustCompile("//.*\r?\n").ReplaceAllString(content, "\n")
+	content = regexp.MustCompile("/\\*.*?\\*/").ReplaceAllString(content, "")
+	matches := regexp.MustCompile("\\s*([-.#:\\w\\s]+)\\s*\\{[^}]*}").FindAllStringSubmatch(content, -1)
+
+	cssNames := map[string]bool{}
+	for _, matchGroup := range matches {
+		cssName := strings.TrimSpace(matchGroup[1])
+		cssNames[cssName] = true
+	}
+
+	// collect Chroma builtin CSS names
+	builtin := map[string]bool{}
+	for tokenType, cssName := range chroma.StandardTypes {
+		if tokenType > 0 && cssName != "" {
+			builtin[".chroma ."+cssName] = true
+		}
+	}
+
+	// show the diff
+	println("CSS names not in builtin:")
+	for cssName := range cssNames {
+		if !builtin[cssName] {
+			println(cssName)
+		}
+	}
+	println("----")
+	println("Builtin CSS names not in file:")
+	for cssName := range builtin {
+		if !cssNames[cssName] {
+			println(cssName)
+		}
+	}
+}

web_src/less/chroma/dark.less

@@ -7,17 +7,19 @@
 .chroma .cpf { color: #649bc4; } /* CommentPreprocFile */
 .chroma .cs { color: #9075cd; } /* CommentSpecial */
 .chroma .dl { color: #649bc4; } /* LiteralStringDelimiter */
+.chroma .fm {} /* NameFunctionMagic */
+.chroma .g {} /* Generic */
 .chroma .gd { color: #ffffff; background-color: #5f3737; } /* GenericDeleted */
 .chroma .ge { color: #ddee30; } /* GenericEmph */
 .chroma .gh { color: #ffaa10; } /* GenericHeading */
 .chroma .gi { color: #ffffff; background-color: #3a523a; } /* GenericInserted */
+.chroma .gl {} /* GenericUnderline */
 .chroma .go { color: #777e94; } /* GenericOutput */
 .chroma .gp { color: #ebdbb2; } /* GenericPrompt */
 .chroma .gr { color: #ff4433; } /* GenericError */
 .chroma .gs { color: #ebdbb2; } /* GenericStrong */
 .chroma .gt { color: #ff7540; } /* GenericTraceback */
 .chroma .gu { color: #b8bb26; } /* GenericSubheading */
-.chroma .hl { background-color: #3f424d; } /* LineHighlight */
 .chroma .il { color: #649bc4; } /* LiteralNumberIntegerLong */
 .chroma .k { color: #ff7540; } /* Keyword */
 .chroma .kc { color: #649bc4; } /* KeywordConstant */
@@ -25,16 +27,16 @@
 .chroma .kn { color: #ffaa10; } /* KeywordNamespace */
 .chroma .kp { color: #5f8700; } /* KeywordPseudo */
 .chroma .kr { color: #ff7540; } /* KeywordReserved */
-.chroma .kt { color: #fabd2f; } /* KeywordType */
+.chroma .kt { color: #ff7b72; } /* KeywordType */
-.chroma .ln { color: #7f8699; } /* LineNumbers */
+.chroma .l {} /* Literal */
-.chroma .lnt { color: #7f8699; } /* LineNumbersTable */
+.chroma .ld {} /* LiteralDate */
 .chroma .m { color: #649bc4; } /* LiteralNumber */
 .chroma .mb { color: #649bc4; } /* LiteralNumberBin */
 .chroma .mf { color: #649bc4; } /* LiteralNumberFloat */
 .chroma .mh { color: #649bc4; } /* LiteralNumberHex */
 .chroma .mi { color: #649bc4; } /* LiteralNumberInteger */
 .chroma .mo { color: #649bc4; } /* LiteralNumberOct */
-.chroma .n { color: #fabd2f; } /* Name */
+.chroma .n { color: #c9d1d9; } /* Name */
 .chroma .na { color: #b8bb26; } /* NameAttribute */
 .chroma .nb { color: #fabd2f; } /* NameBuiltin */
 .chroma .nc { color: #ffaa10; } /* NameClass */
@@ -51,6 +53,7 @@
 .chroma .o { color: #ff7540; } /* Operator */
 .chroma .ow { color: #5f8700; } /* OperatorWord */
 .chroma .p { color: #d2d4db; } /* Punctuation */
+.chroma .py {} /* NameProperty */
 .chroma .s { color: #b8bb26; } /* LiteralString */
 .chroma .s1 { color: #b8bb26; } /* LiteralStringSingle */
 .chroma .s2 { color: #b8bb26; } /* LiteralStringDouble */
@@ -67,4 +70,5 @@
 .chroma .vc { color: #ff7540; } /* NameVariableClass */
 .chroma .vg { color: #ffaa10; } /* NameVariableGlobal */
 .chroma .vi { color: #ffaa10; } /* NameVariableInstance */
+.chroma .vm {} /* NameVariableMagic */
 .chroma .w { color: #7f8699; } /* TextWhitespace */

web_src/less/chroma/light.less

@@ -7,16 +7,19 @@
 .chroma .cpf { color: #4c4dbc; } /* CommentPreprocFile */
 .chroma .cs { color: #999999; } /* CommentSpecial */
 .chroma .dl { color: #106303; } /* LiteralStringDelimiter */
+.chroma .fm {} /* NameFunctionMagic */
+.chroma .g {} /* Generic */
 .chroma .gd { color: #000000; background-color: #ffdddd; } /* GenericDeleted */
 .chroma .ge { color: #000000; } /* GenericEmph */
 .chroma .gh { color: #999999; } /* GenericHeading */
 .chroma .gi { color: #000000; background-color: #ddffdd; } /* GenericInserted */
+.chroma .gl {} /* GenericUnderline */
 .chroma .go { color: #888888; } /* GenericOutput */
 .chroma .gp { color: #555555; } /* GenericPrompt */
 .chroma .gr { color: #aa0000; } /* GenericError */
+.chroma .gs {} /* GenericStrong */
 .chroma .gt { color: #aa0000; } /* GenericTraceback */
 .chroma .gu { color: #aaaaaa; } /* GenericSubheading */
-.chroma .hl { background-color: #e5e5e5; } /* LineHighlight */
 .chroma .il { color: #009999; } /* LiteralNumberIntegerLong */
 .chroma .k { color: #d73a49; } /* Keyword */
 .chroma .kc { color: #d73a49; } /* KeywordConstant */
@@ -25,14 +28,15 @@
 .chroma .kp { color: #d73a49; } /* KeywordPseudo */
 .chroma .kr { color: #d73a49; } /* KeywordReserved */
 .chroma .kt { color: #445588; } /* KeywordType */
-.chroma .ln { color: #7f7f7f; } /* LineNumbers */
+.chroma .l {} /* Literal */
-.chroma .lnt { color: #7f7f7f; } /* LineNumbersTable */
+.chroma .ld {} /* LiteralDate */
 .chroma .m { color: #009999; } /* LiteralNumber */
 .chroma .mb { color: #009999; } /* LiteralNumberBin */
 .chroma .mf { color: #009999; } /* LiteralNumberFloat */
 .chroma .mh { color: #009999; } /* LiteralNumberHex */
 .chroma .mi { color: #009999; } /* LiteralNumberInteger */
 .chroma .mo { color: #009999; } /* LiteralNumberOct */
+.chroma .n {} /* Name */
 .chroma .na { color: #d73a49; } /* NameAttribute */
 .chroma .nb { color: #005cc5; } /* NameBuiltin */
 .chroma .nc { color: #445588; } /* NameClass */
@@ -48,6 +52,8 @@
 .chroma .nx { color: #24292e; } /* NameOther */
 .chroma .o { color: #d73a49; } /* Operator */
 .chroma .ow { color: #d73a49; } /* OperatorWord */
+.chroma .p {} /* Punctuation */
+.chroma .py {} /* NameProperty */
 .chroma .s { color: #106303; } /* LiteralString */
 .chroma .s1 { color: #cc7a00; } /* LiteralStringSingle */
 .chroma .s2 { color: #106303; } /* LiteralStringDouble */
@@ -64,4 +70,5 @@
 .chroma .vc { color: #008080; } /* NameVariableClass */
 .chroma .vg { color: #008080; } /* NameVariableGlobal */
 .chroma .vi { color: #008080; } /* NameVariableInstance */
+.chroma .vm {} /* NameVariableMagic */
 .chroma .w { color: #bbbbbb; } /* TextWhitespace */

web_src/less/themes/theme-arc-green.less

@@ -1,3 +1,4 @@
+@import "../chroma/base.less";
 @import "../chroma/dark.less";
 @import "../codemirror/dark.less";