Is it possible to fully hide a class?

[Co3co]

Is there a way completely hide all unoccupied tag buttons for river/tags? What I want to do is basically the same thing that the hide vacant tags dwm patch does. I have tried setting these properties:

font-size: 0;
min-width: 0;
min-height: 0;
margin: 0;
padding: 0;
border: 0;
opacity: 0;
background-color: transparent;

But they do not fully hide the tags. I still see blank space where the tags should be, and I'm still able to click on the unoccupied tags to focus them. I also tried display: none; and visibility: hidden;, but they were not valid properties.