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

body {
    display: flex;
    justify-content: center;
    align-items: center;
}

/* Let the Google Pay button fill the iframe; the merchant sizes the iframe itself. */
#GooglePayDiv {
    width: 100%;
    height: 100%;
}

#GooglePayDiv .gpay-card-info-container,
#GooglePayDiv .gpay-button {
    width: 100%;
    height: 100%;
}