message: Change color of difficulty stars to darker shade of gray
diff: <span class="fa-4x fa-layers fa-fw">
  <svg style="fill:url(#{{difficulty}})" class="svg-inline--fa fa-star fa-w-18" aria-hidden="true" data-prefix="fa" data-icon="star" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512" data-fa-i2svg="">
  <linearGradient ng-attr-id="{{difficulty}}" x1="0" x2="0" y1="0" y2="100%">
  - <stop ng-attr-offset="{{challenges ? getOffset(challenges,difficulty) : '100%'}}" stop-color="grey"/>
  + <stop ng-attr-offset="{{challenges ? getOffset(challenges,difficulty) : '100%'}}" stop-color="#1C1E22"/>
  <stop ng-attr-offset="{{challenges ? getOffset(challenges,difficulty) : '100%'}}" stop-color="#FA7D2B"/>
  </linearGradient>
  <path fill="{{challenges[difficulty].levelComplete ? '#64AA00' : 'inherit'}}"
  