This new integration will allow the ability to define css in existing style sheets or in style tags. The following css styles are supported (as defined by Stripe):
font-family, font-size, font-smoothing, font-style, font-variant, font-weight, icon-color, line-height, letter-spacing, text-align, text-decoration, text-shadow, text-transform, and color.
You can further define each action as a style in the #[div-id] .mm-stripe-elements-container .[action] where [div-id] can be #mm_field_cc_number_div, #mm_field_cc_cvv_div, or #mm_field_cc_exp_div and action can be base, invalid, or complete.
Example:
#mm_field_cc_number_div .mm-stripe-elements-container .complete {
font-size: 42px;
font-family: Verdana;
color: yellow;
line-height: 50px;
}