This issue seems to be solved in Firefox 67 version: 1527048
When using Firefox on a computer with dark GTK theme, Firefox renders input fields using a dark theme. In some cases, input in fields are unreadable, because field is dark and the text is black.
Most of the pages work fine, because they have CSS themed form fields, which override the default GTK theme.
For the last couple of years, I have used a browser plugin to fix field rendering. But lately, there was a rise in browser plugins which were sold to unethical companies, which modified plugins to spy on user data or inject custom ads.
For some time I have felt uneasy, because of a rise of such threats. Recently I have stumbled upon a way how to solve this issue without browser plugin.
- In Firefox URL bar enter about:config.
- Create new String value with name
widget.content.gtk-theme-override(Right click > new > String)
- Set value to
Adwaita:light(if your distribution does not use GNOME desktop, you should use a name of light GTK theme which is installed on your PC)
- Restart browser
Enjoy better browsing experience. I hope this post was helpful.
As always feel free to ask questions in the comment section.