[BUG] Diff rendering: bold/code text invisible on red (deleted) background lines

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Blacking out of text

<img width="1556" height="573" alt="Image" src="https://github.com/user-attachments/assets/7b2d6063-d85f-4b8c-9849-c278bea83e82" />
<img width="1534" height="522" alt="Image" src="https://github.com/user-attachments/assets/f233bfde-ff44-47f3-a60d-3a1f5b343c86" />

<img width="1580" height="98" alt="Image" src="https://github.com/user-attachments/assets/7ca834f6-9e10-40d8-9077-3d7a55135161" />

What Should Happen?

Normal text should be clearly shown

Error Messages/Logs

Steps to Reproduce

Claude Code edits a file that contains markdown bold (text) or backtick code in the deleted lines; the text becomes invisible against the red diff background

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.174 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_