Not applicable

Hi ​@Alice Bidet 

You can use this custom question javascript, change the style attributes to what you want.

Qualtrics.SurveyEngine.addOnReady(function () {
  var qid = this.questionId;
  var container = document.getElementById('question-' + qid) || document.getElementById(qid);
  if (!container) return;

  var labels = container.querySelectorAll('.slider-na label, .n-a-container label.answer');

  var i;
  for (i = 0; i < labels.length; i++) {
    var label = labels[i];
    label.style.fontWeight = 'bold';
    label.style.fontSize = '14px';
    label.style.cursor = 'pointer';

    var wrapper = label.closest('.slider-na, .n-a-container');
    var input = wrapper ? wrapper.querySelector('input[type="checkbox"]') : null;
    (function (lbl, inp) {
      function paint() {
        lbl.style.color = inp && inp.checked ? '#F3853B' : '#47C3D3';
      }
      if (inp) inp.addEventListener('change', paint);
      paint();
    })(label, input);
  }
});