.birthdatepicker_container{
    display: flex;
    width: 100%;
}
.birthdatepicker_container .birthday{
    flex-basis: 100%;
    margin: 0 10px;
}
.birthdatepicker_container .birthday.birthdatepicker_day{
    margin-left:0;
}
.birthdatepicker_container .birthday.birthdatepicker_year{
    margin-right:0;
}