Making the background of the Contact Form widget transparent

I’m trying to produce a transparent background on the Site Origin Widgets contact form – and I did some custom css that works (would be nice to be able to have transparency as a choice in the contact form design area :-) ).

.so-widget-sow-contact-form-default-9881c33d4b2d .sow-contact-form {
    background-color: transparent;
}

However, when I then made a change to padding of the contact form, it broke my background transparency, because the selector for the form’s parent changed. What I thought was a unique code for the instance of the form, turned out to be a unique code for the particular configuration of the form, and when I changed that configuration, the code changed.

.so-widget-sow-contact-form-default-66e098ae91fe .sow-contact-form {
    padding: 0px;
    border: #c0c0c0 none 0px;
    background-color: #f2f2f2;
}

Am I missing a way to override the form styling that won’t be affected by future changes to other elements of the form?