Centreing Recaptcha on newsletter

Site URL: https://jodistewartart.com

My recaptcha button was showing after the submit button on the newsletter sign up. I added code I found on one of the forums to correct it, which it did, but now the button won't centre, even after adding more code to correct it. Can anyone have a look at what I've got and suggest a solution because I don't understand code at all - I'm just copying and pasting. Squarespace 'help' has been unhelpful. Any advice would be appreciated at this stage because I'm losing my mind.

This is the code I have

/* reCaptcha position */
.newsletter-form-body {
    display: flex;
    flex-direction: column;
    justify-content: center !important;
    align-items: center;
}

.captcha-container {
    order: 2;
    margin-top: 20px;
}
.newsletter-form-button-wrapper.submit-wrapper {
    order: 3;
    margin-top: 0;
}

.captcha-container.align-left.rendered {
    margin-left: auto;
    margin-right: auto;
}

Add to Design > Custom CSS

div.captcha-container div {
    margin: 0 auto;
}

thank you so much