Problem with background color implementation for a specific list view

Hi

I want to make the background-color of a specific list view gray.

What I did was;

1 - adding a class to the list view "grijs"

2 - adding in the custom.css this

.grijs > li { background-color: #f5f5f5 !important; }

.grijs > li:hover { background-color: #f5f5f5 !important; }

3 - adding in the custom .scss also the same; .grijs > li { background-color: #f5f5f5 !important; }

.grijs > li:hover { background-color: #f5f5f5 !important; }

The result; list view keeps having the original color. I see that my new class is not even read (yes I did a cache delete);

mx-listview .mx-listview-item { background-color: #fff; }

This is what I see...who can tell me which mistake I make?