[BUG] Wrong syntax highlighting Github Light theme in the File viewer tab (Desktop client)

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?

The File viewer tab does not use the same syntax highlighting theme as the diff/working-tree viewer (Themes: Github Light theme and etc.).

In the diff view (left panel), Python is highlighted correctly: keywords, identifiers, strings and numbers all get distinct colors from the active theme.

In the File view (right panel, src/main.py), the same file is rendered with a different, broken palette — most of the code (identifiers, operators, punctuation, function calls) is painted in a single reddish/brown color, and only a few tokens keep the expected theme colors. The two panels show the identical lines side by side, so the difference is clearly a theming bug, not a language-detection issue.

Additionally, the first visible lines in both panels are clipped/overlapped by the panel header (see the top of the screenshot with Github Light theme).

<img width="1643" height="625" alt="Image" src="https://github.com/user-attachments/assets/0b2bd64e-92e9-41b5-aead-f74d70f38cf4" />

What Should Happen?

The File viewer tab should use the same syntax highlighting theme as the diff viewer, so that the same file looks identical (aside from the diff markers) in both panels. Content should also not be clipped by the panel header.

Error Messages/Logs

<img width="1643" height="625" alt="Image" src="https://github.com/user-attachments/assets/0b2bd64e-92e9-41b5-aead-f74d70f38cf4" />

Steps to Reproduce

1. Open a session that modifies a Python file (e.g. src/main.py).
2. Open the working tree / diff panel — highlighting is correct.
3. Open the same file in the File tab.
4. Compare the two panels: the File tab uses a different, mostly monochrome-red palette.

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Not CLI. Latest available Desktop version

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_