Hi.Regarding your suggestion to use Dev Tool, the "Please fill in this field" pop-up does not show up at all in the inspector panel.
Now it has become more clear.
This is a standard browser validation message. Such a message cannot be stylized using CSS since its appearance depends on the system, browser and color scheme (light/dark mode).
An alternative way is to disable browser validation messages and replace them with your own. In this case, you will need not only CSS, but also JavaScript. Google subject or search on stackoverflow.com to find examples
For example
Code:
https://stackoverflow.com/questions/67161694/html-default-validation-messages-styling
Statistics: Posted by Pavel-ww — Tue Nov 05, 2024 7:55 am