- is () : One of the things that allow us to write more than CSS selectors in short, and make it easier for us to do a lot of CSS operations, including reducing code lines and increasing the efficiency of the code in CSS.
It is possible through these examples that you understand what I want to convey.
In this example, you see a simple and small need. The difference may not be clear. see with me if there is a large example, the difference may be a factor in how.
This can be clearly between the topic and on a scale of projects and the code will be complex, the importance of :is() and the code will be added and easy to modify.
The :is() is very similar to the nested operation in the CSS preprocessor.
:is( ) is supported in all browsers except IE (internet explorer).
Finally, you can look at these links and you will understand them better.