fix(editor): Match PyCharm syntax colours and text weight

Greyscale antialiasing mapped to `-webkit-font-smoothing: antialiased`,
which drops macOS stem darkening, so editor and UI text rendered thinner
and syntax colours looked lighter than PyCharm's. Use `auto` instead.

Align lezer tag mappings with PyCharm's Light scheme:
- HTML/XML: `<!doctype>` is plain text (documentMeta is a sub-tag of meta).
- CSS/SCSS/Sass: property names use the attribute colour; values and units
  the attribute-value colour; class, id, pseudo, colour and url() the tag colour.
- YAML: keys are keywords.
- Markdown: quotes are strings with keyword markers, link destinations
  italic function colour, titles strings, horizontal rules keywords.

Claude-Session: https://claude.ai/code/session_01SaPPsVPuk6ZTNsoUCNCbMv

src/editor/core/cm/highlight.ts

@@ -18,6 +18,9 @@ function token(tag: Tag | Tag[], name: string, defaults: { italic?: string; bold
 }
 
 export const openideaHighlightStyle = HighlightStyle.define([
+  // Markdown tags whole links / quotes; listed first so marks, URL and title inside keep their own colours.
+  token(t.link, "link", { effect: "underline" }),
+  token(t.quote, "string"),
   token([t.keyword, t.controlKeyword, t.moduleKeyword, t.operatorKeyword, t.definitionKeyword, t.modifier, t.null, t.bool, t.unit], "keyword"),
   token(t.self, "self"),
   token([t.string, t.special(t.string), t.character, t.attributeValue], "string"),
@@ -31,7 +34,9 @@ export const openideaHighlightStyle = HighlightStyle.define([
   token([t.function(t.definition(t.variableName)), t.definition(t.function(t.variableName)), t.function(t.definition(t.propertyName))], "function"),
   token([t.comment, t.lineComment, t.blockComment], "comment", { italic: "var(--syn-comment-style)" }),
   token(t.docComment, "doc-comment", { italic: "italic" }),
-  token([t.meta, t.annotation, t.macroName, t.documentMeta], "decorator"),
+  token([t.meta, t.annotation, t.macroName], "decorator"),
+  // `<!doctype>` is a sub-tag of `meta`; PyCharm leaves the XML prologue as plain text.
+  { tag: t.documentMeta, color: "var(--fg-editor)" },
   token([t.constant(t.variableName), t.atom, t.special(t.variableName)], "constant", { italic: "italic" }),
   token(t.labelName, "constant"),
   token([t.variableName, t.definition(t.variableName), t.local(t.variableName)], "variable"),
@@ -46,9 +51,10 @@ export const openideaHighlightStyle = HighlightStyle.define([
   { tag: t.emphasis, fontStyle: "italic" },
   { tag: t.strong, fontWeight: "600" },
   { tag: t.strikethrough, textDecoration: "line-through" },
-  token([t.link, t.url], "link", { effect: "underline" }),
+  // Markdown, as IntelliJ: link destination like a static method, rules like markers.
+  token(t.url, "function", { italic: "italic" }),
   token(t.monospace, "markup-code"),
-  token(t.quote, "comment"),
+  token(t.contentSeparator, "keyword"),
   { tag: t.inserted, color: "var(--vcs-added)" },
   { tag: t.deleted, color: "var(--danger)" },
   { tag: t.changed, color: "var(--vcs-modified)" },

src/editor/core/cm/languages.ts

@@ -63,9 +63,25 @@ export function loadSupport(desc: LanguageDescription): Promise<LanguageSupport
   return p;
 }
 
-/** Highlighting the stock grammars lack (IntelliJ colours annotations; @lezer/java tags them as plain identifiers). */
+/**
+ * PyCharm CSS colours: selectors fall back to HTML tag name, property names to
+ * HTML attribute name, values and units to HTML attribute value.
+ */
+const CSS_TAGS: Parameters<typeof styleTags>[0] = {
+  "FeatureName PropertyName": t.attributeName,
+  "ValueName FontName Unit": t.attributeValue,
+  "ClassName IdName PseudoClassName ColorLiteral CallTag": t.tagName,
+};
+
+/** Highlighting the stock grammars lack or colour unlike IntelliJ. */
 const EXTRA_TAGS: Record<string, Parameters<typeof styleTags>[0]> = {
+  // @lezer/java tags annotations as plain identifiers.
   Java: { "MarkerAnnotation/Identifier Annotation/Identifier MarkerAnnotation Annotation": t.annotation },
+  CSS: CSS_TAGS,
+  SCSS: CSS_TAGS,
+  Sass: CSS_TAGS,
+  // YAML keys are keywords in IntelliJ.
+  YAML: { "Key/Literal Key/QuotedLiteral": t.keyword },
 };
 
 function patchSupport(desc: LanguageDescription, support: LanguageSupport): LanguageSupport {

src/styles/global.css

@@ -26,7 +26,8 @@ body {
   font-family: var(--font-ui);
   font-size: var(--fs-ui);
   line-height: 1.4;
-  -webkit-font-smoothing: antialiased;
+  /* Greyscale: `auto` keeps macOS stem darkening, as JetBrains IDEs render text. */
+  -webkit-font-smoothing: auto;
   overflow: hidden;
   -webkit-user-select: none;
   user-select: none;
@@ -134,8 +135,9 @@ a:hover {
 :root[data-aa-ide="none"] body {
   -webkit-font-smoothing: none;
 }
+/* `antialiased` drops stem darkening: glyphs and syntax colours render lighter than PyCharm's. */
 :root[data-aa-editor="greyscale"] .cm-editor {
-  -webkit-font-smoothing: antialiased;
+  -webkit-font-smoothing: auto;
 }
 :root[data-aa-editor="subpixel"] .cm-editor {
   -webkit-font-smoothing: subpixel-antialiased;