Bad contrast for Human verification sign up

[jermanuts]

Describe the issue

As title says, here's how it looks currently on dark theme

I already tried

• I've read and searched the documentation.
• I've searched for similar filed issues in this repository.

Steps to reproduce the behavior

Click on Register
Scroll to see "Human verification"

Expected behavior

contrast should be better

Screenshots

Exception traceback

No response

How do you run Weblate?

weblate.org service

Weblate versions

No response

Weblate deploy checks

No response

Additional context

No response