html,
body {
    height: 100%;
}

.bg-body-tertiary {
    --bs-bg-opacity: 1;
    background-color: aliceblue;
}

.form-signin {
    max-width: 500px;
    padding: 1rem;
}

    .form-signin .form-floating:focus-within {
        z-index: 2;
    }