Problem with font colour

Hi,

I have rebranded our account connection page with logo and dark blue background. To make the Login font more readable on dark blue, I set it up to white. This is working properly.

However, when people connect for the first time, and have to change their password, then the page that instruct to enter a new password has the correct branding, but has black font, which is difficult to read. How can I change the colour of font on that page? I could not find any settings for it.

Thanks in advance for your help.