body,html{
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    position: relative;
} 

.login{
width: 300px;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%,-50%);
text-align: center;
}
.btnIni{
    margin-bottom: 1em;
}
@media(max-width:400px){
    .login{
        width: 90%;
    }
}