Diff view: low-contrast backgrounds after switching to native installer

Current behavior

When Claude Code displays file edits (diffs), removed lines are shown with a dark red/maroon background and added lines with a dark green background. The text color remains the same as the syntax highlighting. The result is low contrast — the red and green backgrounds are muted and blend together, making it harder to quickly distinguish additions from deletions at a glance.

Desired behavior

Removed lines should have a bright red background with white text, and added lines should have a bright green background with white text (or dark text). This was the behavior in the npm-installed version of Claude Code. The higher contrast made diffs much more scannable and the added/removed sections immediately visually distinct.

Context

This changed when switching from the npm-installed Claude Code (@anthropic-ai/claude-code via npm) to the native installer. No terminal or VS Code settings were changed. The terminal used is VS Code's integrated terminal.

Request

Either restore the previous higher-contrast diff style as the default, or add a configuration option to choose between diff rendering styles (e.g., high-contrast vs muted backgrounds).