.thingi{position:absolute; inset:0}

.thingi::before{
  content:"";
  position:absolute; left:50.5%; top:50%;
  width:70%; height:70%;
  transform:translate(-50%,-50%);
  background:currentColor;               /* gets white from fa-inverse */
  -webkit-mask:url("/assets/icons/thingiverse.svg") no-repeat 50% 50% / contain;
  mask:url("/assets/icons/thingiverse.svg") no-repeat 50% 50% / contain;
}