popup text not visible in dark theme

[ScottishLemur]

Checklist

• I've already searched in existing issues and haven't found a similar problem reported.
• I'm using the latest version of the app
• This error caused the app to crash
• This error is reproducible

Which category best fits this error?

User Interface

App version

1.6.1

Reproduction steps

1. Setup ReadYou to use dark theme
2. Switch to dark theme
3. Open any articles
4. Long touch a word until a popup appears

actual behaviour

The text inside the popup is not visible.
No issue with light theme

screenshot

Crash report