Why am I not seeing red and green colors?

This is due to 'High Contrast' being turned on in your Android accessibility settings

Depending on your manufacturer (i.e. Google Pixel, Samsung), this setting is located in different places.

Please check in your phone Settings under accessibility to see if high contrast mode is on. High contrast mode will disable all font colors in the app.

Google Pixel 9a, Android 15 Home Screen > Settings > Display & touch > Display size and text > turn off 'High contrast text'

Samsung S23, Android 13 Home Screen > Settings> Accessibility > Visibility enhancements > turn off 'High contrast fonts'