.input-group>.input-group-append>.btn, .input-group>.input-group-append>.input-group-text, .input-group>.input-group-prepend:first-child>.btn:not(:first-child), .input-group>.input-group-prepend:first-child>.input-group-text:not(:first-child), .input-group>.input-group-prepend:not(:first-child)>.btn, .input-group>.input-group-prepend:not(:first-child)>.input-group-text
{
    border-top-left-radius: .25rem !important;
    border-bottom-left-radius: .25rem !important;
    border-top-right-radius: 0px !important;
    border-bottom-right-radius: 0px !important;
}

#txtDateOfBirth
{
    border-top-left-radius: 0px !important;
    border-bottom-left-radius: 0px !important;
    border-top-right-radius: .25rem !important;
    border-bottom-right-radius: .25rem !important;
    border-right: 1px solid #ced4da;
}

.input-group-append 
{
    margin-right: -1px;
    margin-left: auto;
}