Why does the category hover state not appear but the link hover state does?

Question

The selector is at line 23
https://code.sololearn.com/WxF41f64Dx0i/?ref=app

Answer 1

It works depending on your browser. Since you're using the app it will only show hover when you press your finger on it. If you are are viewing from a desktop browser then hover shows while the courser is moving over it.

Answer 2

change background color to any other and see.

edit:
it's working.
violet to red or blue and see?