CSS content empty rules
This means that the URL in question is a CSS file that contains one or more empty rules.
Why is this important?
Most of the time, empty rules appear as a result of refactoring without further cleanup. Empty rules add unnecessary bytes to the file size and, although minimal, increase browser resources for rendering.
What does the Hint check?
This Hint will trigger for any internal or external CSS URL which contains empty rules.
Examples that trigger this Hint:
The Hint would trigger for any style sheet that contains at least one empty rule.
All of the examples below would trigger the Hint:
How do you resolve this issue?
Empty rules add nothing, but cause additional work for the browser, and as such should simply be removed. Eliminating empty rules results in smaller file sizes and less style information for the browser to deal with.