CSS3 appearance Property

.thing {
   -webkit-appearance: none;
   -moz-appearance:    none;
   appearance:         none;
}
select::-ms-expand {display:none}
select{
   position:relative;
   border:0;
   -webkit-appearance:none;
   -moz-appearance:none;
   appearance:none;
   text-indent:0.01px;
   text-overflow: '';
}

https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-appearance