How can I keep the slider handle hidden until someone clicks on the slider?

To avoid my participants from being anchored, I would like to hide the handle until they click somewhere along the slider. I am entirely new to Qualtrics and have never worked with code like this before. On this forum, I found this code:
var q = jQuery("#"+this.questionId);
q.find(".handle").css('visibility', 'hidden');
q.find(".track").on("click", function() {
jQuery(this).find(".handle").css('visibility', 'visible');
});
But when I go to Look&Feel -> Style -> Custom CSS and paste this code, nothing changes for me.
Any help would be greatly appreciated!