wp-admin-filter-post-types-date-range-datepicker-filter.css

.filter_date_range_wrapper{
    position:relative;
    display:inline-block;
    vertical-align:bottom;
}
.filter_date_range_wrapper > span{
    position:absolute;
    top:8px;
    right:6px;
    color:#ccc;
}
.filter_date_range_wrapper > span:after{
    content: "\f145";
    font-size: 16px;
    line-height: 1;
    font-family: dashicons;
    font-weight: 400;
    font-style: normal;
    text-align: center;
}

.filter_date_range_wrapper.active > span{
    cursor:pointer;
}

.filter_date_range_wrapper.active > span:after{
    content: "\f158";
}

.filter_date_range_wrapper.active > span:hover{
    color:#555;
}