Line break on mobile view

Hi, 

In a matrix table, I have a code that generates a line break before the “I don’t know” scale. The code works well on desktop view but the line does not appear on mobile view.

Any ideas how to fix this? 

This is the code I’m using: 

Qualtrics.SurveyEngine.addOnload(function() {
    var q = jQuery("#"+this.questionId);
    var cl = q.find('td.ColumnLabels:first'); 
    if(cl.length > 0) cl.attr('colspan', cl.attr('colspan') - 1);
    if(q.find('div.desktop').length > 0) q.find('.last').css("border-right", "1px solid #BBBBBB");
});

Thanks!