form .form-control {
    position: relative;
    box-sizing: border-box;
}

form .form-control:focus {
    z-index: 2;
}

form .username {
    margin-bottom: -1px;
    border-bottom-right-radius: 0;
    border-bottom-left-radius: 0;
}
form .password {
    border-top-left-radius: 0;
    border-top-right-radius: 0;
}