body { margin: 0px; }
.login{
    width:100%;
    max-width: 200px;
    position: absolute;
    left: 50%;
    top: 50%;
    -webkit-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
}
.login input[type="text"]{
    width:100%
}
.login input[type="password"]{
    width:100%
}
.login input[type="button"]{
    width:50%;
    float:right;
}