Hi,
Well, the only I was able to find is from this stack overflow thread. Basically this custom CSS:
.asp_ss select {
background: url("data:image/svg+xml,<svg height='10px' width='10px' viewBox='0 0 16 16' fill='%23000000' xmlns='http://www.w3.org/2000/svg'><path d='M7.247 11.14 2.451 5.658C1.885 5.013 2.345 4 3.204 4h9.592a1 1 0 0 1 .753 1.659l-4.796 5.48a1 1 0 0 1-1.506 0z'/></svg>") no-repeat !important;
background-position: calc(100% - 0.75rem) center !important;
appearance: none !important;
}It should yield a very similar output to what you are looking for.