html,body{
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
}
#login{
    background-image: url(../img/login.jpg);
    height: 100%;
}

#form{
    width: 420px;
    height: 400px;
    position: absolute;
    left: calc(50% - 210px);
    top: calc(50% - 200px);
    color: white;
    text-align: center;
}

button{
    width: 140px;
}

