[FEATURE] Customizable Code Snippet Colors / Syntax Highlighting Theme

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Claude Code currently uses fixed syntax highlighting colors for code snippets in the CLI output. For users with custom terminal color schemes (particularly dark backgrounds), certain code colors can be difficult or impossible to read due to insufficient contrast.

Specific Issue: With a dark blue iTerm background, some of Claude Code's default dark syntax highlighting colors are nearly invisible, making code snippets hard to review and understand.

Visual Example

See attached screenshot showing the readability issue: the dark blue text used for markdown file previews is completely unreadable against a dark blue terminal background. The large block of text in the middle of the output is effectively invisible, making it difficult to review file contents without physically highlighting text with your cursor before taking action.

<img width="470" height="350" alt="Image" src="https://github.com/user-attachments/assets/0721b4bc-ffbc-42cd-9e3f-76325aa51d5a" />

Current Limitations

(according to a Claude-driven diagnosis of the issue/options)

• No ability to customize individual syntax highlighting colors
• No theme selection (light/dark variants, preset themes)
• Only option is CLAUDE_CODE_SYNTAX_HIGHLIGHT=false to completely disable highlighting
• Must modify terminal color scheme globally, affecting all applications

Proposed Solution

Option 1: Theme Selection (Minimal)

Add preset themes that work well with common terminal backgrounds:

{
  "display": {
    "syntaxTheme": "light" | "dark" | "high-contrast" | "none"
  }
}

Option 2: Color Overrides (Moderate)

Allow users to override specific syntax highlighting categories:

{
  "display": {
    "syntaxColors": {
      "keyword": "#ff79c6",
      "string": "#50fa7b",
      "comment": "#6272a4",
      "function": "#8be9fd",
      "number": "#bd93f9"
    }
  }
}

Option 3: Named Theme Support (Advanced)

Support popular terminal themes (Dracula, Solarized, Nord, etc.):

{
  "display": {
    "syntaxTheme": "dracula" | "solarized-dark" | "nord" | "gruvbox"
  }
}

Alternative Solutions

Have tried editing all color settings in iterm.

Priority

Medium - Would be very helpful

Feature Category

Configuration and settings

Use Case Example

_No response_

Additional Context

_No response_