[Feature]: [Accessibility] Legibility issue in assertion diff in UI mode (light theme)

[kumarchandresh]

🚀 Feature Request

I really cannot see the letter on the red background in the assertion diff of UI mode (light theme). Doesn't anyone else feel the same?

The legibility issue is not there in the dark mode.

Example

No response

Motivation

I prefer to work in light mode.

[manimovassagh]

Would a PR for this be welcome?

I traced the root cause: the ErrorMessage component in packages/web/src/components/errorMessage.tsx calls ansi2html() without defaultColors. When expect matchers use ANSI reverse video (code 7) to highlight changed characters in assertion diffs, the foreground color is left undefined and inherits the page's dark text color — producing dark text on a dark red background.

The HTML reporter's testErrorView.tsx already passes defaultColors to ansi2html(), so the fix is aligning the shared component with the same pattern. Happy to include a test as well.