Reply To: Box around SUBMIT ORDER button

Yeah it appears to be coming from the plugins css code –

.mm-checkoutSection .mm-purchaseSection {
    clear: both;
    background: #fff;
    overflow: auto;
    border-radius: 5px;
    padding: 10px 0px 10px 0px;
}

So you would need to add some css (in your style.css file) to override it –

.mm-checkoutSection .mm-purchaseSection {
    background: none !important;
}