body {
margin:0px;
}

main {
    display: flex;
    align-items: center;
    justify-items: center;
    justify-content: center;
    background-color: blue;
    width:100vw;
    height: 100vh;

}

#login {
    background-color: red;
    max-width: 100px;
    max-height: 100px;
    padding:20px;
}