.tablesort
{
    display: inline-block;
    width: 16px;
    height: 16px;
    background-size: 100%;
}
.tablesort--asc
{
    background-image: url(../image/twistie-down.svg);
}
.tablesort--desc
{
    background-image: url(../image/twistie-up.svg);
}