In the latest Firefox 70 Beta release, a feature called ” Inactive CSS ” (inactive CSS) was introduced, and the new DevTool tool will show developers which CSS properties will not affect the selected elements and why, which will greatly save developers time.
The specific case is that when an element is selected, if the CSS attribute of the element has no effect on it, a message box will appear next to the attribute, indicating that it will not work and explain the reason.
🌅 Now in Beta: Inactive CSS!
We show you which CSS properties aren’t affecting the selected element and why.
— Firefox DevTools (@FirefoxDevTools) September 11, 2019