main {
    background: black;
    #login {
        margin: 100px auto 0 auto; width: 100%; max-width: 400px;
        form {
            width: 100%;
            display: flex; flex-direction: column; align-items: center; gap: 10px;
            padding: 10px;
            #username, #password {
                width: 100%;
            }
            label {
                align-self: start;
            }
            #btn-login {
                margin-top: 20px;
            }
            .error {
                margin-top: 20px;
                color: red;
            }
        }
    }
}