refactor(chat): remove dead syntaxTheme plumbing

The Prism syntaxTheme prop is no longer read after code highlighting moved to
the Shiki worker. Remove the now-dead prop threading and its source.

- Drop syntaxTheme from interfaces, destructures, prop passes, and React.memo
  comparators across ChatMessage, MessageBody, ProgressiveGroup, ToolPart,
  TurnActivity, ToolOutputDialog, and ChatInput.
- Drop the unused _syntaxTheme param from renderWebSearchOutput.
- Remove the dead generateSyntaxTheme usages (ChatMessage memo, PlanView
  unassigned memo) and delete the now-unimported syntaxThemeGenerator module.

packages/ui/src/components/chat/ChatInput.tsx

@@ -4557,7 +4557,6 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
         <ToolOutputDialog
             popup={attachmentPreview}
             onOpenChange={handleAttachmentPreviewOpenChange}
-            syntaxTheme={{}}
             isMobile={isMobile}
         />
         </>

packages/ui/src/components/chat/ChatMessage.tsx

@@ -2,7 +2,6 @@ import React from 'react';
 import type { Message, Part } from '@opencode-ai/sdk/v2';
 import { useShallow } from 'zustand/react/shallow';
 
-import { defaultCodeDark, defaultCodeLight } from '@/lib/codeTheme';
 import { MessageFreshnessDetector } from '@/lib/messageFreshness';
 import { useConfigStore } from '@/stores/useConfigStore';
 import { useFeatureFlagsStore } from '@/stores/useFeatureFlagsStore';
@@ -12,7 +11,6 @@ import { useSessionUIStore } from '@/sync/session-ui-store';
 import { useSelectionStore } from '@/sync/selection-store';
 import { useDeviceInfo } from '@/lib/device';
 import { useThemeSystem } from '@/contexts/useThemeSystem';
-import { generateSyntaxTheme } from '@/lib/theme/syntaxThemeGenerator';
 import { cn } from '@/lib/utils';
 
 import type { AnimationHandlers, ContentChangeReason } from '@/hooks/useChatAutoFollow';
@@ -548,13 +546,6 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
         return false;
     }, [themeVariant]);
 
-    const syntaxTheme = React.useMemo(() => {
-        if (currentTheme) {
-            return generateSyntaxTheme(currentTheme);
-        }
-        return isDarkTheme ? defaultCodeDark : defaultCodeLight;
-    }, [currentTheme, isDarkTheme]);
-
     const shouldAnimateMessage = React.useMemo(() => {
         if (isUser) return false;
         const freshnessDetector = MessageFreshnessDetector.getInstance();
@@ -1026,7 +1017,6 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
                                                 isUser={isUser}
                                                 isMessageCompleted={isMessageCompleted}
                                                 messageFinish={messageFinish}
-                                                syntaxTheme={syntaxTheme}
                                                  isMobile={isMobile}
                                                  alwaysShowActions={alwaysShowMessageActions}
                                                  hasTouchInput={hasTouchInput}
@@ -1060,7 +1050,6 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
                                                 isUser={isUser}
                                                 isMessageCompleted={isMessageCompleted}
                                                 messageFinish={messageFinish}
-                                                syntaxTheme={syntaxTheme}
                                                  isMobile={isMobile}
                                                  alwaysShowActions={alwaysShowMessageActions}
                                                  hasTouchInput={hasTouchInput}
@@ -1113,7 +1102,6 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
                                 messageFinish={messageFinish}
                                 messageCompletedAt={messageCompletedAt ?? undefined}
                                 messageCreatedAt={messageCreatedAt ?? undefined}
-                                syntaxTheme={syntaxTheme}
                                  isMobile={isMobile}
                                  alwaysShowActions={alwaysShowMessageActions}
                                  hasTouchInput={hasTouchInput}
@@ -1146,7 +1134,6 @@ const ChatMessage: React.FC<ChatMessageProps> = ({
                 <ToolOutputDialog
                     popup={popupContent}
                     onOpenChange={handlePopupChange}
-                    syntaxTheme={syntaxTheme}
                     isMobile={isMobile}
                 />
             </React.Suspense>

packages/ui/src/components/chat/components/TurnActivity.tsx

@@ -17,7 +17,6 @@ interface TurnActivityProps {
     isExpanded: boolean;
     collapsedPreviewCount?: number;
     onToggle: () => void;
-    syntaxTheme: Record<string, React.CSSProperties>;
     isMobile: boolean;
     expandedTools: Set<string>;
     onToggleTool: (toolId: string) => void;

packages/ui/src/components/chat/message/MessageBody.tsx

@@ -337,7 +337,6 @@ interface MessageBodyProps {
     messageCompletedAt?: number;
     messageCreatedAt?: number;
 
-    syntaxTheme: { [key: string]: React.CSSProperties };
 
     isMobile: boolean;
     alwaysShowActions?: boolean;
@@ -950,7 +949,6 @@ const AssistantMessageBody = React.memo(({
     messageCompletedAt,
     messageCreatedAt,
 
-    syntaxTheme,
     isMobile,
     alwaysShowActions,
     hasTouchInput,
@@ -1642,7 +1640,6 @@ const AssistantMessageBody = React.memo(({
                             isExpanded={turnGroupingContext.isGroupExpanded === true}
                             collapsedPreviewCount={collapsedPreviewCount}
                             onToggle={toggleActivityGroup}
-                            syntaxTheme={syntaxTheme}
                             isMobile={isMobile}
                             expandedTools={expandedTools}
                             onToggleTool={onToggleTool}
@@ -1794,7 +1791,6 @@ const AssistantMessageBody = React.memo(({
                                     part={toolPart}
                                     isExpanded={expandedTools.has(toolPart.id)}
                                     onToggle={onToggleTool}
-                                    syntaxTheme={syntaxTheme}
                                     isMobile={isMobile}
                                     alwaysShowActions={alwaysShowMessageActions}
                                     onContentChange={onContentChange}
@@ -1866,7 +1862,6 @@ const AssistantMessageBody = React.memo(({
         effectiveStreamPhase,
         showReasoningTraces,
         shouldDeferSortedInlineText,
-        syntaxTheme,
         toggleActivityGroup,
         turnGroupingContext,
         visibleParts,

packages/ui/src/components/chat/message/ToolOutputDialog.tsx

@@ -32,7 +32,6 @@ import { runtimeFetch } from '@/lib/runtime-fetch';
 interface ToolOutputDialogProps {
     popup: ToolPopupContent;
     onOpenChange: (open: boolean) => void;
-    syntaxTheme: { [key: string]: React.CSSProperties };
     isMobile: boolean;
 }
 
@@ -984,7 +983,7 @@ const MermaidPreviewDialog: React.FC<{
     return createPortal(content, document.body);
 };
 
-const ToolOutputDialog: React.FC<ToolOutputDialogProps> = ({ popup, onOpenChange, syntaxTheme, isMobile }) => {
+const ToolOutputDialog: React.FC<ToolOutputDialogProps> = ({ popup, onOpenChange, isMobile }) => {
     const { t } = useI18n();
     const [diffViewMode, setDiffViewMode] = React.useState<DiffViewMode>('unified');
     const pierreThemeConfig = usePierreThemeConfig();
@@ -1170,7 +1169,7 @@ const ToolOutputDialog: React.FC<ToolOutputDialogProps> = ({ popup, onOpenChange
 
                                 if (tool === 'web-search' || tool === 'websearch' || tool === 'search_web') {
                                     return (
-                                        renderWebSearchOutput(popup.content, syntaxTheme) || (
+                                        renderWebSearchOutput(popup.content) || (
                                             <WorkerHighlightedCode
                                                 language="text"
                                                 code={popup.content}

packages/ui/src/components/chat/message/parts/ProgressiveGroup.tsx

@@ -35,7 +35,6 @@ interface ProgressiveGroupProps {
     isExpanded: boolean;
     collapsedPreviewCount?: number;
     onToggle: () => void;
-    syntaxTheme: Record<string, React.CSSProperties>;
     isMobile: boolean;
     expandedTools: Set<string>;
     onToggleTool: (toolId: string) => void;
@@ -373,7 +372,6 @@ type AggregatedRow =
 interface ExpandableToolRowProps {
     activity: TurnActivityPart;
     isExpanded: boolean;
-    syntaxTheme: Record<string, React.CSSProperties>;
     isMobile: boolean;
     onToggleTool: (toolId: string) => void;
     onShowPopup: (content: ToolPopupContent) => void;
@@ -385,7 +383,6 @@ interface ExpandableToolRowProps {
 const ExpandableToolRow: React.FC<ExpandableToolRowProps> = ({
     activity,
     isExpanded,
-    syntaxTheme,
     isMobile,
     onToggleTool,
     onShowPopup,
@@ -402,7 +399,6 @@ const ExpandableToolRow: React.FC<ExpandableToolRowProps> = ({
             part={activity.part as ToolPartType}
             isExpanded={isExpanded}
             onToggle={handleToggle}
-            syntaxTheme={syntaxTheme}
             isMobile={isMobile}
             onContentChange={onContentChange}
             onShowPopup={onShowPopup}
@@ -425,7 +421,6 @@ const ExpandableToolRow: React.FC<ExpandableToolRowProps> = ({
 
 const MemoExpandableToolRow = React.memo(ExpandableToolRow, (prev, next) => {
     return prev.isExpanded === next.isExpanded
-        && prev.syntaxTheme === next.syntaxTheme
         && prev.isMobile === next.isMobile
         && prev.onToggleTool === next.onToggleTool
         && prev.onShowPopup === next.onShowPopup
@@ -826,7 +821,6 @@ const ProgressiveGroup: React.FC<ProgressiveGroupProps> = ({
     isExpanded,
     collapsedPreviewCount = 0,
     onToggle,
-    syntaxTheme,
     isMobile,
     expandedTools,
     onToggleTool,
@@ -915,7 +909,6 @@ const ProgressiveGroup: React.FC<ProgressiveGroupProps> = ({
                         key={row.activity.id}
                         activity={row.activity}
                         isExpanded={expandedTools.has(row.activity.id)}
-                        syntaxTheme={syntaxTheme}
                         isMobile={isMobile}
                         onToggleTool={onToggleTool}
                         onShowPopup={onShowPopup}
@@ -942,7 +935,6 @@ const ProgressiveGroup: React.FC<ProgressiveGroupProps> = ({
                         key={row.activity.id}
                         activity={row.activity}
                         isExpanded={expandedTools.has(row.activity.id)}
-                        syntaxTheme={syntaxTheme}
                         isMobile={isMobile}
                         onToggleTool={onToggleTool}
                         onShowPopup={onShowPopup}

packages/ui/src/components/chat/message/parts/ToolPart.tsx

@@ -59,7 +59,6 @@ interface ToolPartProps {
     part: ToolPartType;
     isExpanded: boolean;
     onToggle: (toolId: string) => void;
-    syntaxTheme: { [key: string]: React.CSSProperties };
     isMobile: boolean;
     alwaysShowActions?: boolean;
     onContentChange?: (reason?: ContentChangeReason) => void;
@@ -843,7 +842,6 @@ const ToolScrollableTextOutput: React.FC<{
     part: ToolPartType;
     metadata: Record<string, unknown> | undefined;
     input: Record<string, unknown> | undefined;
-    syntaxTheme: { [key: string]: React.CSSProperties };
 }> = ({ output, part, metadata, input }) => {
     const { t } = useI18n();
     const renderedOutput = getToolOutputText(output, part, metadata);
@@ -1594,7 +1592,6 @@ DiffPreview.displayName = 'DiffPreview';
 interface ToolExpandedContentProps {
     part: ToolPartType;
     state: ToolStateUnion;
-    syntaxTheme: { [key: string]: React.CSSProperties };
     currentDirectory: string;
     isExpanded: boolean;
     onShowPopup?: (content: ToolPopupContent) => void;
@@ -1603,7 +1600,6 @@ interface ToolExpandedContentProps {
 const ToolExpandedContent: React.FC<ToolExpandedContentProps> = React.memo(({
     part,
     state,
-    syntaxTheme,
     currentDirectory,
     isExpanded,
     onShowPopup,
@@ -1853,7 +1849,6 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = React.memo(({
                     part={part}
                     metadata={metadata}
                     input={input}
-                    syntaxTheme={syntaxTheme}
                 />,
                 {
                     className: part.tool === 'bash' ? 'p-1 rounded-none' : 'p-1',
@@ -1944,7 +1939,6 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
     part,
     isExpanded,
     onToggle,
-    syntaxTheme,
     isMobile,
     onContentChange,
     onShowPopup,
@@ -2844,7 +2838,6 @@ const ToolPartContent: React.FC<ToolPartProps> = ({
                             <ToolExpandedContent
                                 part={part}
                                 state={state}
-                                syntaxTheme={syntaxTheme}
                                 currentDirectory={currentDirectory}
                                 isExpanded={isExpanded}
                                 onShowPopup={onShowPopup}
@@ -2926,7 +2919,6 @@ const ToolPart: React.FC<ToolPartProps> = (props) => {
 export default React.memo(ToolPart, (prev, next) => {
     return areRenderRelevantPartsEqual([prev.part], [next.part])
         && prev.isExpanded === next.isExpanded
-        && prev.syntaxTheme === next.syntaxTheme
         && prev.isMobile === next.isMobile
         && prev.alwaysShowActions === next.alwaysShowActions
         && prev.onContentChange === next.onContentChange

packages/ui/src/components/chat/message/toolRenderers.tsx

@@ -510,7 +510,7 @@ export const renderTodoOutput = (
     }
 };
 
-export const renderWebSearchOutput = (output: string, _syntaxTheme: { [key: string]: React.CSSProperties }, options?: { unstyled?: boolean }) => {
+export const renderWebSearchOutput = (output: string, options?: { unstyled?: boolean }) => {
     try {
         return (
             <div

packages/ui/src/components/views/PlanView.tsx

@@ -18,7 +18,6 @@ import { buildCodeMirrorCommentWidgets, normalizeLineRange, useInlineCommentCont
 import { getLanguageFromExtension } from '@/lib/toolHelpers';
 import { useDeviceInfo } from '@/lib/device';
 import { useThemeSystem } from '@/contexts/useThemeSystem';
-import { generateSyntaxTheme } from '@/lib/theme/syntaxThemeGenerator';
 import { createFlexokiCodeMirrorTheme } from '@/lib/codemirror/flexokiTheme';
 import { languageByExtension } from '@/lib/codemirror/languageByExtension';
 import { useSessionUIStore } from '@/sync/session-ui-store';
@@ -164,7 +163,6 @@ export const PlanView: React.FC<PlanViewProps> = ({ targetPath = null }) => {
   const runtimeApis = useRuntimeAPIs();
   const { isMobile } = useDeviceInfo();
   const { currentTheme } = useThemeSystem();
-  React.useMemo(() => generateSyntaxTheme(currentTheme), [currentTheme]);
 
   const session = React.useMemo(() => {
     if (!currentSessionId) return null;

packages/ui/src/lib/theme/syntaxThemeGenerator.ts

@@ -1,208 +0,0 @@
-import type { Theme } from '@/types/theme';
-
-export function generateSyntaxTheme(theme: Theme) {
-  const syntax = theme.colors.syntax;
-  const surface = theme.colors.surface;
-
-  return {
-    'code[class*="language-"]': {
-      color: syntax.base.foreground,
-      background: 'transparent',
-      fontFamily: 'Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace',
-      fontSize: '1em',
-      textAlign: 'left' as const,
-      whiteSpace: 'pre',
-      wordSpacing: 'normal',
-      wordBreak: 'normal' as const,
-      wordWrap: 'normal' as const,
-      lineHeight: '1.5',
-      MozTabSize: '4',
-      OTabSize: '4',
-      tabSize: '4',
-      WebkitHyphens: 'none' as const,
-      MozHyphens: 'none' as const,
-      msHyphens: 'none' as const,
-      hyphens: 'none' as const,
-    },
-    'pre[class*="language-"]': {
-      color: syntax.base.foreground,
-      background: 'transparent',
-      fontFamily: 'Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace',
-      fontSize: '1em',
-      textAlign: 'left' as const,
-      whiteSpace: 'pre',
-      wordSpacing: 'normal',
-      wordBreak: 'normal' as const,
-      wordWrap: 'normal' as const,
-      lineHeight: '1.5',
-      MozTabSize: '4',
-      OTabSize: '4',
-      tabSize: '4',
-      WebkitHyphens: 'none' as const,
-      MozHyphens: 'none' as const,
-      msHyphens: 'none' as const,
-      hyphens: 'none' as const,
-      padding: '0',
-      margin: '0',
-      overflow: 'auto',
-    },
-
-    comment: {
-      color: syntax.base.comment,
-      fontStyle: 'italic',
-    },
-    prolog: {
-      color: syntax.base.comment,
-    },
-    doctype: {
-      color: syntax.base.comment,
-    },
-    cdata: {
-      color: syntax.base.comment,
-    },
-
-    punctuation: {
-      color: syntax.tokens?.punctuation || surface.mutedForeground,
-    },
-
-    property: {
-      color: syntax.tokens?.variableProperty || syntax.base.variable,
-    },
-    tag: {
-      color: syntax.tokens?.tag || syntax.base.keyword,
-    },
-    'attr-name': {
-      color: syntax.tokens?.tagAttribute || syntax.base.variable,
-    },
-    'attr-value': {
-      color: syntax.tokens?.tagAttributeValue || syntax.base.string,
-    },
-
-    boolean: {
-      color: syntax.tokens?.boolean || syntax.base.number,
-    },
-    number: {
-      color: syntax.base.number,
-    },
-    constant: {
-      color: syntax.tokens?.constant || syntax.base.number,
-    },
-    symbol: {
-      color: syntax.tokens?.constant || syntax.base.number,
-    },
-
-    string: {
-      color: syntax.base.string,
-    },
-    char: {
-      color: syntax.base.string,
-    },
-
-    function: {
-      color: syntax.base.function,
-    },
-    builtin: {
-      color: syntax.tokens?.functionBuiltin || syntax.base.function,
-    },
-
-    'class-name': {
-      color: syntax.tokens?.className || syntax.base.type,
-    },
-    namespace: {
-      color: syntax.tokens?.namespace || syntax.base.type,
-      opacity: 0.8,
-    },
-
-    keyword: {
-      color: syntax.base.keyword,
-    },
-    atrule: {
-      color: syntax.base.keyword,
-    },
-    selector: {
-      color: syntax.base.function,
-    },
-
-    operator: {
-      color: syntax.base.operator,
-    },
-
-    variable: {
-      color: syntax.base.variable,
-    },
-
-    regex: {
-      color: syntax.tokens?.regex || syntax.base.string,
-    },
-
-    url: {
-      color: syntax.base.function,
-      textDecoration: 'underline',
-    },
-    entity: {
-      color: syntax.base.function,
-      cursor: 'help',
-    },
-
-    '.language-css .token.string': {
-      color: syntax.base.string,
-    },
-    '.style .token.string': {
-      color: syntax.base.string,
-    },
-
-    deleted: {
-      color: theme.colors.status.error,
-      backgroundColor: theme.colors.status.errorBackground,
-    },
-    inserted: {
-      color: theme.colors.status.success,
-      backgroundColor: theme.colors.status.successBackground,
-    },
-
-    title: {
-      color: theme.colors.primary.base,
-      fontWeight: 'bold',
-    },
-    'code-block': {
-      color: syntax.base.string,
-    },
-    'code-snippet': {
-      color: syntax.base.string,
-    },
-    list: {
-      color: syntax.base.variable,
-    },
-    hr: {
-      color: surface.mutedForeground,
-    },
-    table: {
-      color: syntax.base.function,
-    },
-    blockquote: {
-      color: surface.mutedForeground,
-      fontStyle: 'italic',
-    },
-
-    important: {
-      color: syntax.base.keyword,
-      fontWeight: 'bold',
-    },
-    bold: {
-      fontWeight: 'bold',
-    },
-    italic: {
-      fontStyle: 'italic',
-    },
-    strike: {
-      textDecoration: 'line-through',
-    },
-
-    decorator: {
-      color: syntax.tokens?.decorator || syntax.base.function,
-    },
-    annotation: {
-      color: syntax.tokens?.decorator || syntax.base.function,
-    },
-  };
-}